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FAQs About Water Changes for Marine Systems 3

Related Articles: Marine Water Change, The "Perfect" Water Change Regimen? by Scott Fellman, Water Changes, Exchanges by Anthony Calfo, Captive Seawater Quality, General  Marine Maintenance

Related FAQs: Water Changes for Marine Systems 1, Water Changes 2, Water Changes 4, & FAQs on Water Changes: Rationale, Gear/Tools, Frequency/Amount, TechniquesAutomation, Trouble/shooting, & Water Top-Off Systems, Evaporation/Water Make-Up, Treating Tapwater Marine Water QualityMarine Plumbing

Substrate vacuuming - reef tank 10/25/05 Hi Guys and Gals, Now, I REALLY DO try to read as much as I can on WWM and other web sites before I ask a question.  <Good>  You all have been very, very helpful many, many times. In this case I have found exact opposite answers on WWM, so I thought I'd ask directly and maybe you can put it to a vote ;).  I have a 55G reef tank, lots of live rock, about 2-3" sand bed. Beside the low-bio-load of corals and fish, there is a crew of hermits and Astrea snails along with an orange-spotted goby. Should I manually vacuum the substrate, <Yes>  and if so, how deeply? <it doesn't matter...just make sure you get all the detritus out of the gravel...or you may have nitrate and algae problems> Doesn't that suck all the little critters out of the bed? <probably not>  I have a siphon-type vacuum, but I've never actually used it on my reef tank..... <It should be fine, IanB>  <<Please Google our site for tips on vacuuming sand beds - "Marina, vacuum, sand bed", select the link that says 'cached'.  MH>>

SW gravel vacuuming 10/10/05 Hi Again Mr. Fenner, I read on WWM about the cleaning of live sand during a water change. Again I do have an undergravel filter in there and whether or not it's actually doing anything, I'd like to keep it clean so that I don't encounter the negative factors of the UG filter. So, here's what I found Re: Live Sand.  I was hoping that I would be able use the Python and clean the tank better. <You can... but "cleanliness is not sterility"... you don't want to "clean" the substrate too well> I was thinking of just stirring the sand and with a fine net removing the particles that come up out of the sand but I was told that would kill bacteria and produce more nitrate is this true? <No... consider the alternatives... and their results. Bob Fenner> So basically are you saying that it is OK to stir up the sand on the substrate to remove debris without killing nitrifying bacteria? <Mmm, it's okay, just don't be too fastidious> I have a cleaner shrimp and that star fish and I don't know if they  help with the cleaning process. Besides I'm not sure if any small particulate got trapped in the sand from the UG filter or not, and if so I want to get it out. Being said, if I stir up the sand and all the gunk goes everywhere, then what, am I responsible for trying to get it all out or will it just settle back down and be taken care of  by the inverts?  Forgive me for being naive in this matter. I have only worked with crushed coral in the past in which I just siphoned and  most of the stuff trapped in the substrate just slipped up into the hose. Now the sand goes right with the water and debris. I know I shouldn't have an UG filter in my tank especially with reef sand, but it's there, and I really don't want to cause a disaster removing it,  <You won't... you can siphon it out... replace it, abandon the UG filters, just leave the plates in place...> so is there anything that you are able to add in order for me to keep it from potentially causing any harm? Again, it seems like a little bit of a different story with live sand, than with gravel or crushed coral.  I know I should search more and I am trying, but I trust and appreciate your direct advice. Thanks again for everything! -Jon <Better for you to search, come to understand the many related issues, side-issues... the "logic" behind WWM is this exactly... to help people gain insights into a/the "big picture"... not really "just what they seemingly want to know right now". Cheers, Bob Fenner> <<Use our Google bar, search on "Marina, deep sand bed, vacuum/ing" and you should find the technique I learned at the Long Beach Aquarium.>> 

Tank Volume Capacity + Water change routines, lighting measures  9/21/05    Hi WWM crew, <Vince> I am a long time reader but first time writer. Firstly, thanks to you guys, I have a thriving mini reef aquarium which has enabled me to fulfill this long time desired ambition. <Congrats!> I would greatly appreciate if you could answer my questions which I could not find definitive answers for in your archives. Question 1. When calculating tank volume for lighting, should only the actual water volume in the display be used. i.e. total space water volume capacity - 20% for contents displacement, or should the total space volume of the display area be used to determine the theoretical watts required per gallon rule ? <The watts per gallon "rule" is a real "groaner" for me (and others)... much more would need to be formulated to give such a guestimate utility... like the depth to photosynthetic livestock, dissolved color... much more to it/this> Question 2. I currently have a calculated 250 litre water volume tank with Aqua C EV 180 skimmer & 20 x tank volume water circulation. I won't go into my tank inhabitants as I would embarrass myself knowing you guys would definitely reprimand me for overstocking. Current water parameter readings are Nitrite 0 , Nitrate approx. 5 -10ppm , PH 8.4 ,  Salinity 1.024 , I don't have an accurate phosphate reading but judging by the minimal nuisance algae growth present I will assume it is within acceptable levels. I do a 50 litre fortnightly saltwater change plus input approx. 3.5 litres a day of RO/DI top off water equating to a total of 200 litres or 80% of water volume changes a month. Given the thriving state of my tank inhabitants I am reluctant to change this routine but I would like to know, if, in your opinion, I could cut down to a monthly 50 litre salt water change instead of each fortnight. <I would not> This would bring the total monthly water change down from 80% to 75%. <Mmm, the "top-off" water does not count as water change...> Given the fact that I am a little overstocked with inhabitants but the filtration seems capable of dealing with the volume presented , do you think I would have to add additional trace elements if I go down to a monthly 50 litre saltwater change routine ? <I would not start "fooling" with such... unless you could/would/will measure for each element, compound... To put this to you concisely: I would not change your current routine>   I guess I am trying to get experienced opinions of cost versus effort. I.e. if I have to add additional trace elements but it only adds up to the cost of salt then I would benefit from only having to perform 1 water change a month instead of two. Looking forward to reading your answers / opinions.     Regards Vince <More being gained by the two week change-outs my friend. Cheers, Bob Fenner>

Corals out of water - 9/14/05 Hi Mr. Fenner! <Paul here to help> Thanks for the last reply! I only forgot to ask about SPS and the water line. I know one should initially place corals 4" below surface and that is what I did. My Pocillopora is now noticeably growing. When I do my weekly water change it gets very close to the lowered water line. Within months I wont be able to do water changes without having part of the coral emerged. So is it bad to have a SPS coral (Pocillopora and Montipora species) partly out of the water for (at the worse) 30 minutes each week? <OK. Well, I have the exact same issue with the exact same corals. The short answer is for a short time, I would say I haven't experienced any issues with bleaching or color problems or anything of that nature. Any longer than that though, I would have to think you might see some issues. Now all this depends on the water replacement, health of the coral, lights on or off etc. I use raw natural seawater from Monterey Bay, I feed my tank a mish mash of Mysid shrimp, Cyclop-eeze, enriched brine, and other stuff, and I do try to water changes with the lights on but not always. Of course there are many more factors that I am sure could be an issue and/or might affect the corals ability to be above water for a short time. For some corals in the surf zone this isn't an issue, but the corals you mention aren't technically surf zone corals. Try and see. Let me know what you find. ~Paul> Thanks again!!! Dominique

Re: Changing water - 9/19/05 Hi Paul! I also meant that when you do successive water changes (over a short period of time) the following water change not only removes aged water but also the new water that is now in the tank. <I agree with that> For example, if you replace 50% of the water in the morning and then 50% in the evening you have not done a 100% water change but rather a 75% water change (for with the evening water change you would also have removed 50% of the still new water that has mixed with the old water in the tank, so to speak...). < Yes but I think we are worrying too much on just water removal and not enough on the chemistry. The key is to make sure the chemistry of your water is where it should be for the animals in your tank.> However I have been calculating those things this morning and I must say it's over thought. <ahhhh....yes.> Based on the same logic, a 35% water change each two weeks would in fact sum to a 30% water change if done at 5% each day during those two weeks. A 15% water change each two weeks would in fact sums to a 13% water change if done at 1% each day during those two weeks. And so on. Even then, new water isn't new after a week so this factor is really not a concern. < well, yes, may be true.> So the only things left are the positive effects of very gradual water change. <Eureka!> Bottom line: you're right, there is no reason not to do smaller water changes each day. So that is just what I will come to: replace only 1.5% of the water each day instead of 20% each two weeks. Tell me what you think about my babbling if you have a second. ;) <Well, to me, it seems you came to the same conclusions. So it is fine with me. ~Paul> Thanks! Dominique A MORE Perfect Water Change Routine! 8/24/05 All, <Hi there! Scott F. here tonight!> I read your article on the "perfect" water change regimen, and now have a question. The article suggested 5% water changes twice weekly, but it also implied that this was in conjunction with a skimmer. <Yep...I highly recommended combo, IMO!> So, if I am running a skimmerless nano (20L), should I do larger changes at the same interval? I currently change 5 gal NSW twice weekly, your system would have me changing only 1 gal twice weekly. My corals are thriving and my fish (Banggai cardinals) are breeding, so maybe I am answering my own question here, but just wanted to get a professional opinion about the 'skimmerless' issue. Thanks, James <Good question, James. Of course, being the water change fanatic that I am, I'll recommend sticking with the water change regimen that you already employ! In my opinion, it's all about consistency and observation. Your 2- 5 gallon water changes are working well in your system, and I certainly would not reduce them if you're happy with the results. As you've seen us state time and again here on WWM, nano reef tanks require a much higher level of attention to husbandry than larger tanks, because of their inherent instability, so I like your idea of the large water changes. I like the idea of smaller, more frequent water changes, because they help remove dissolved organics before they have a chance to accumulate and degrade the water quality, which is why I wrote the article. It's so easy and beneficial-and it becomes a part of your tank routine very quickly. In the absence of a skimmer, your water change routine is your best ally, and I'm happy to hear that you're employing it successfully! Best of luck to you! Regards, Scott F.>

Hawk/Centropyge compatibility, safeness of milk jugs 8/19/05 Hi, I have a couple of non-related questions please.  I have a 75 gallon saltwater tank currently with 1 large flame hawk and 2 false perculas. I purchased a coral beauty angel a couple of months ago and everything seemed fine until about a week ago.  I noticed its fins were ragged and it quit eating.  I had noticed the hawk chasing the angel several times while feeding.  The angel died yesterday.  Is it possible that if I bought another angel this might not happen again?  I know nothing is guaranteed. <Will very likely re-occur> Also, I keep my water to compensate for evaporation in plastic milk jugs.  Should I change out the jugs after a while.  I have read about water getting bacteria in it from plastics breaking down, but didn't know if there was anything to worry about with fish.  thanks for your help, James <Don't think there is any reason to change, toss these containers. Bob Fenner>

Formula for calculating percentage of water changed w/ a flow through system 8/3/05 Hi <Hello> Do you know of any formula that one can use to calculate what percentage of an aquarium's water is changed out based on a known qty of gallons/minute which comes in and drains out? (I don't know if you can decipher what I'm trying to ask, so I'll try to give an example of what I'm trying to figure out). example: 100 gallon tank water flows in and out at 5 gallons a minute Now I know that if I start a water change using these numbers, and do a four minute change, I've drained and refilled a total of 20 gallons. However, I also know that's not the same as a 20% water change, because some of the water going out is the same water that just came in. So, is there a formula for figuring what percentage of the original tank's contents has been changed after the four minutes of running the flow through system? <Better... to remove the water to be changed first, and then replace it... rather than mix> I'm almost positive I read an article related to this very subject several years ago in either TFH or FAMA, however, I wouldn't even begin to know where to start looking to find it, if that's even where I saw it to begin with. I've spent about an hour and a half online (including your site), with no answer thus far. Thanks for your time. Gary B. <Mmm, well, can/could be calculated... as an integrated function... or guessed at pretty closed as a percentage per some time interval change (like how much is new, how much is old, how much is mixed... per minute of the change-time)... But replacing after removal will get you the most benefit/s. Bob Fenner> Water Changes/DSB Critters - 07/19/05 Hello Eric, <<Howdy James!>> Thank you again for your help and advice.  I have listened to you many times in the past and will do so again. <<Ahh, power <G>...I'll try not to abuse it...>> At the moment I change 10% of my water a week with natural seawater. <<Mmm...still using the NSW eh.>> This amounts to just under 40 gallons.  I have 8 fish around 3 to 5 inches so I am not overstocked. <<Depends on the fish, but likely so in this case.>> I also have a very efficient Aquamedic Baby skimmer. <<Good>> So do you think I could get away with a 10% change every 2 weeks? <<I hate to dissuade anyone from 10% weekly water changes if they are already doing them, but give it a try and observe occupants/test for debilitating changes in water chemistry.  Likely a bi-weekly change of 10% will be fine.>> Here in Cape Town I can get IO salt and Aquamedic salt.  As with many things the salt over here is much more expensive than the USA. <<Yes...and we still moan about the cost <G>.>> The pH of our local seawater is 8.6.  So you are right, making my own will be much better. <<Mmm...pH is fine...my concern is lack of a buffer pool (rapid drop in alkalinity), parasites, disease/pollution...>> My DSB refugium has been running for a month now.  It has 5 inches of 1-2mm size aragonite.  I can see no life of any kind in there, should there be? <<Yes, something...even after only a month (alga's, micro-crustaceans).>> Should I add anything else? <<Can you light this 'fuge?  If so I would add some macro algae (Chaetomorpha or Gracilaria).  If not lighting/macro algae, add a couple pieces of live rock to "kick start" your critters.>> When I go real close to the glass, my Regal Tang comes up to me, then the black part of him completely turns into a bronze/gold colour.  This really impresses my friends.  Why does he do this? <<I've always found these tangs to be especially "skittish."  I had one in particular that even after 8 years, would "freak out" every time I approached the tank.  The loss of color is a sign of stress/disturbance/mood...the tang is merely reacting to the presence of the "large strange creature" invading its domain.>> Many Thanks, James. <<Always welcome my friend, Eric R.>>

Water Changes - 07/26/05 Hi Eric, <<Hello James>> Due to the cost of the salt etc. I can make 600 litres of RO water and AquaMedic salt to last 6 weeks.  So should I change 100 litres every week or 200 litres every 2 weeks? <<Considering your system is 400 gallons, I would do the 200 liters every two weeks.>> Also, what is the ideal salinity for a FOWLR, 1.022,23,24,25? <<Lots of differing opinions on this.  Any of these could be fine but my preference is closer to natural seawater salinity (1.025/026).>> I have finally found a guy with Chaetomorpha through sareefkeepers.com. <<Excellent!>> You told me about the stuff ages but I could never find any. <<Glad you kept up the hunt <G>.>> I'll send you some pics of my tank so you know what we have been discussing. <<Looking forward to it.>> Many Thanks, James. <<Regards my friend, Eric R.>>

Major Water Change??? Actually algae control, gaining sufficient knowledge 7/14/05 Hello <Hi there> First and foremost, thank you for hosting such and excellent site, very informative.  I have an issue regarding green water in my saltwater aquarium.  I had this issue once before and my local pet store determined that my water was fine, but, I was not supplying my live rock with a calcium buffer.  I purchased the Kent Marine Tech CB Buffers and the green water went away within two weeks.  Here are the specifics on my tank setup: 29 Gallon Saltwater Tank 1 X 65W 10,000K Daylight & 460nm Actinic w/ Lunar Light Powercompact Remora Aqua C skimmer 2 - Penguin 550 Powerheads at opposing corners 30lbs of Live Rock pH 8.4 ammonia = 0 nitrites = 0 nitrates = 0 alkalinity = normal (no numbers on the test strip) calcium = 420ppm When the water went green this last time I had a Prizm Skimmer in service, that got replaced by the Remora after reading your opinion on the Prizm. Also, I had only one powerhead before reading your website.  Plus I have made weekly 20% water changes.  The water has cleared some but you can hardly make out the live rock, yes, it's that bad.  The residents of the tank are a yellow watchman goby, lawnmower blenny, flame Hawkfish, fire clownfish, sea cucumber, 8 hermit crabs, 4 turbo grazers and an anemone.   Before reading your site, I had made the error of resting a piece of live rock against the glass.  I understand now that this is affecting circulation throughout the tank.  My problem is, since I can't see into the tank clearly enough, I don't want to move around the live rock.  My question is, do I proceed with a major water change, i.e. 50% so that I can at least do that? <Unless there was some compelling reason, I would not (ever) change more than 25% of the water in an established system. Much more likelihood of trouble...> Thank you for your help John Fey <John... please read here re Algae Control: http://www.wetwebmedia.com/algaeconMar.htm and the linked files above... till you formulate a plan of action here... I would check for phosphate, perhaps employ a chemical filtrant... consider adding a sump/refugium, biological control means... Bob Fenner>

Water Changes I am sorry, I should have elaborated more.  I have 1 base piece of cured live rock that is about 8 pounds.  I have an additional 125 pounds of rock (not yet live).  I have been adding calcium additive every other day to assist in coralline growth on additional rock.  I have seen the growth of coralline on rock already at 5 days.  Tank is already starting to show brown algae.  I also have 4 green chromis to assist in cycling.  Not sure when 1st livestock would or should be, but based on your answer I take it that I would not need to make any water changes until additional livestock is introduced.  I also have a 40 gallon sump broken into 3 chambers.  A chamber for the skimmer, 2nd chamber containing live sand and live rock fragments and a 3rd return chamber.  <Jason, the Chromis' are very hardy and you need not change water.  Before buying display specimens, I would do a 10% water change, then 10% weekly thereafter.  James (Salty Dog)>

"Was he serious?!"  Topping off Marine with Fresh water Bob and Crew; <Mike G here> If I happen across a LFS while I'm out and about, I make a point of stopping in to see their selection of both supplies and Marine livestock (if any). I found one of those today, and the attendant and I got to talking. Anyway, to make a long story short, he insisted that it was perfectly okay to top off a marine tank with regular freshwater. <That it is.> The notion seemed... -How to put this- ...Odd. Would this practice not tend to dilute the existing mix, and therefore lower the specific gravity of the tank? <Actually, no. For this notion to make sense, one must understand that, when water evaporates, just that happens: water evaporates. Any salts, heavy metals, or dissolved materials do not evaporate. They instead remain in solution. For example, envision a tank with a ratio of 5:5, water to salt. Let's pretend this is optimal salinity. Note that this tank is not topped off at all. If one part water evaporates, 1 part salt does not. So, you are left with a ratio of 4:5. If another part water evaporates, you will be left with a ratio of 3:5. The salinity will rise rapidly. If you were to top this tank off as it evaporated with salt water, it would again begin with our optimal salinity of 5:5. Once one part of water evaporates, it is topped off with one part salt and 1 part water (saltwater). As salt does not evaporate, the salinity ratio becomes 5:6. If it evaporates and is topped off with salt water again, the ratio will become 5:7, then 5:8, and so forth. As a final example, envision this same tank that is topped off with fresh water. It, again, begins with 5:5. If one part water evaporates, and one part water replaces that, the ratio remains at 5:5. As a side note, this does not hold true for water changes. As water and salt are in solution together, removing 2 parts water by water change will also remove 2 parts salt, so water change replacement water should always be the same salinity as that of the tank. Hope this clears things up for you.>

Kole Tang and ich problems - Answer to Vacuuming Sandy Substrata de Marina Also how would I gravel vacuum a fine sand substrate? I have the Oolite Aragalive so if I vacuum the bottom the sand comes out also.  <I didn't know you had a fine sand bed. You probably should add (if you don't have) some sand stirring critters. I guess the AquaClear 110 would probably work to a degree, but with a 4" sand bed in the filter I'm thinking that the water flow through the sand won't keep up with the 400+gph pump on the filter.  James (Salty Dog)> >>James, I happen to have more experience vacuuming sandy substrates than I care to, and if you'd like to place an addendum to this, please let's.  These substrates CAN be vacuumed quite effectively, but it requires a VERY LONG (and I do mean very long) vacuum tube.  An equally outrageously long section of flexible tubing is also necessary, this length seems to help "drive" or power the siphon better.  When I worked at the Long Beach Aquarium of the Pacific, one of my regular "chores" (ha! As if it could actually be called a chore!) was to feed and care for the baby bamboo sharks in the coral lab (public display area). They are grown out on sandy substrate, in what for all intents and purposes is essentially a large cat-litter pan.  Filtration and water changes are, of course, quite important, but more so with these little ones. They left quite a bit of uneaten food (even with hand feeding), so I had to vacuum the sand very regularly. The tube was about 3' (three feet) long, with about a 2" diameter. That, along with keeping a kink in the hose (hand-controlled) allowed me good control. There were those who tried to use ball valves in the line, but you just can't get the same control as when you "hand kink" it.  Marina<<

Can my tank be too clean? Dear Bob and Staff, My LFS is telling me that he thinks my tank is too clean and believes I should do less than 2 water changes a month. < I agree with him. > Now for the question. I have a 90 gallon tank set up with a wet/dry filter and 125lbs of live rock. When I clean my tank or blow things off the rock and coral I seem to produce a lot of debris. My thought were to use a canister filter for periodical clean up. < Good idea. > I figured with that pump I can clean the tank and also take the filter pad out of my wet/dry so my skimmer can receive raw water. < Well that is okay.  I don't think I would be in favor of removing filtration items. > Do you think this is a good idea or am I doing too much to the tank like my LFS suggests? < I think a refugium would be much better than a wet dry.  I also think too many water changes isn't really a problem, but I certainly think that frequency is unnecessary. > Thank you!! <  Blundell  >

Water changes.... Hi <How goes it?  Michael here this...guess it's morning, now> First off I need to thank you for the great site that you are running.....what a great help you have been. <You're too kind...standing on the shoulders of giants, here, though!> I have a rather silly question, <Can't be worse than someone not knowing the answer to "when was the war of 1812", can it?> but it has been bugging me for some time now. I've had tanks for many years no, so doing water changes is nothing new to me, but since I've owned a reef tank for about a year now, I always feel a bit unsure of what is going to happen. <Usually you take water out, and replace water, and it mixes with the water you already had in the aquarium...ok sorry feeling a bit hyper ;)> Anyways, The tank is about 30 gals, with a small 3 gal sump for the skimmer. I change about 10 gals every 2 weeks. <All good> So the question I have is this. The rockwork is quite high with the corals also close to the water surface. When I do a water change I always make sure that water is still covering the coral. But would a very short exposure time to air do any damage to the corals. <Depends on the coral...many SPS is exposed to the air at least part of every day in the wild.  I would be more worried about light shock than short bursts of water deprivation...turn off the lights if you think they will be exposed to air just to be safe> It is so that I could, if needed do larger water changes. The corals are mainly Sinularia, and Caulastrea. <Hmm, Caulastrea should be fine, but I would be a bit wary of the Sinularia> I am just asking because at the moment, I can change the 10 gals without losing water over the corals, but if I want to add more rock and corals, what is the best way to change the water other than using a liter jug and taking one liter out, and then replacing the liter...........which would take forever!! <Yep!  10 gallons in a 30 gallon system is fine, larger water changes shouldn't be necessary at any one time.  However, the easiest way to perform larger water changes would be to add a 10 or 20 gallon sump\refugium to the system...you'll wonder how you ever got on without one.  You'd never have to worry about corals being exposed, either> Cheers for that, <Anytime> Chris B <M. Maddox>

Nitrates and water change Dear crew, Wonderful website you have here!  Hope you could help me with my query.  I'm from Asia and water test kits here are quite expensive and not too accurate as most of them are near their expiration dates.  As a result, most hobbyists here don't use them at all!  (me included :-).   <I don't either anymore...shhhh! :D> I have a 75 gal marine FOWLR system running for a year now.  Filtration is provided by a protein skimmer powered by a powerhead supplemented by a powerhead connected to an external overhead filter box whose media are some ceramic rings, bio-balls, foam and filter floss. <The filter and bioballs are unnecessary and will contribute to any nitrate problems you may be having.  The live rock and sand are capable of being the sole filtration.>   I have 60 kg.s of live rock and white sand as substrate.  Inhabitants are:  2 yellow damsels, 2 sergeant majors, 1 blue velvet, 1 blue damsel, 1 Foxface, 1 powder brown tang, 1 cleaner shrimp, 1 coral banded shrimp, 4 dancing shrimps, 14 turbo snails, a scallop and 3 tube worms.  I feed once a day with either flakes, pellets and occasionally some frozen bloodworms. <A heavy bioload, but not unmanageable> Incidentally, the Foxface just died a few days ago after being in the system for 2 and a half months but I plan to put in another one .  I top off evaporated water with freshwater every week. <TAP water?  Or RO/DI water?>   I do a water change of 25 gals every 3 months.  I have no idea what my nitrate level is before water change!  With the above information, would you say that my water change program is satisfactory?  Or can I still push my luck and do it every 4 months or perhaps even 5 or 6? <I would bet that you have a pretty high nitrate level.  33% WC once every 4 months is not much at all.  I do 25% water changes monthly on all my FO tanks, and sometimes 50% monthly on the ones with heavy bioload.> Thanks, Carlos Nitrates and water change Dear crew, <Hi there Carlos> Wonderful website you have here!  Hope you could help me with my query.  I'm from Asia and water test kits here are quite expensive and not too accurate as most of them are near their expiration dates.  As a result, most hobbyists here don't use them at all!  (me included :-).   <I don't either... unless something behaviorally seems awry> I have a 75 gal marine FOWLR system running for a year now.  Filtration is provided by a protein skimmer powered by a powerhead supplemented by a powerhead connected to an external overhead filter box whose media are some ceramic rings, bio-balls, foam and filter floss.  I have 60 kg.s of live rock and white sand as substrate.  Inhabitants are:  2 yellow damsels, 2 sergeant majors, 1 blue velvet, 1 blue damsel, 1 Foxface, 1 powder brown tang, 1 cleaner shrimp, 1 coral banded shrimp, 4 dancing shrimps, 14 turbo snails, a scallop and 3 tube worms.  I feed once a day with either flakes, pellets and occasionally some frozen bloodworms. Incidentally, the Foxface just died a few days ago after being in the system for 2 and a half months but I plan to put in another one. <Mmm, might be that your system is too small, has too much Damsel-aggression for a siganid> I top off evaporated water with freshwater every week.  I do a water change of 25 gals every 3 months. <Mmm number two... I'd do more frequent, smaller changes...>   I have no idea what my nitrate level is before water change!  With the above information, would you say that my water change program is satisfactory?  Or can I still push my luck and do it every 4 months or perhaps even 5 or 6? Thanks, Carlos <I'd switch some out, vacuuming the substrate, at least once a month... or even twice... or weekly. Please read Scotter's excellent piece re: http://www.wetwebmedia.com/scottsh2ochgart.htm Bob Fenner>

Buffering RO Water for Water Change 10/26/04 I have been using RO, aerated for a day, salt mix, than aerate few more days for a water change.   <hmmm... do buffer after aeration and before salting if/when used as such> However, I realized the PH was only 8.0 or so when I follow this procedure so I decided to add buffer.   <ah, good> I added about 1/2 teaspoon of Kalk to 25 gallons of water as a buffer after the 1 day aeration.  I noticed the water got really cloudy even after 12 hrs of aeration.   <too much and/or too fast> I added the salt mix anyway thinking that it will clear up. First, is Kalk okay to use as a buffer?   <nope... its not actually a carbonate buffer, not does it impart anything directly to alkalinity. You need a proper buffer (carbonates) for this. Kalk merely supports ALK indirectly (and well)> Secondly, I found that the water is really cloudy even after 2 days of aeration after I mixed in the salt mix. <nope> Is this normal?   <hard to say... it could be amplified by the sea salt mix> Will it clear up with more aeration?  Also, will it be safe to use cloudy water for water change?   >hard to say... but likely so> I've never used Kalk as a buffer for water change but I have been following Anthony's Kalk slurry method religiously with calcium reactors on my tanks.  This is my first time doing this and I don't want to use this water if I messed up something. <no worries... a common mistake. Do consider reading or re-reading my "marble analogy" in the "Book of Coral Propagation" to put calcium and Alk in perspective> I figured I ask the crew first before using this cloudy water mix. Thanks for your help. Roy <best of luck/life. Anthony>

Marine aquariums and septic tanks I have a question?   I was just wondering will the saltwater routine water changes affect my underground septic system for my house I have always had county sewer in the past, but seeming I have an underground septic system and drain field and I am not sure what it is made of , my home is only 3 years old I am assuming that it's not metallic. Your thoughts please, I just don't want to have a premature expense, for a question that has never been brought up to me before. <Good question... there's little physical damage that running marine water along with other material down your septic system, but there might be a biological problem if there was too much marine comparatively. I strongly suspect that you're fine here. Bob Fenner> Re: Add CaCl to water change? Thanks Steve. <You're welcome. Sorry this follow-up is late.> I have tested the fresh saltwater a couple of days after mixing and get 320ppm Ca @ SG 1.024 with a Salifert test kit. <Odd, it ought to mix up more like 380.> When I do a substantial water change after building Ca in the tank to around 380, it always drops because the fresh saltwater is more dilute in terms of Ca. <Yes, that would happen if adding 320.>Is there another brand of synthetic salt that is higher in Ca? <IO should be. Perhaps you should contact Marineland at their website and ask their opinion. I recently switched to the new Oceanic brand and have been very satisfied. Many feel that Tropic Marin is the "gold standard." I do run a calcium reactor, but as you know, that is more of an alk generator than a Ca generator. I also buffer the RO/DI water with Super Buffer before adding salt. It would make life more simple if the synthetic salt had more Ca in it. <adding Seachem Ca would be quick & simple.> What concentration of Cl is too much? <I am not aware of any specific numbers on this.> It looks like I need to add about 240g anhydrous CaCl2 to 200 gallons to raise Ca to 400ppm. Regards, George. <Over time, I think you can keep your Ca up by adding a bit to your change water. You could also try the other two brands I mentioned. Oceanic is also usually priced very competitively and is available at most Petco stores. Do contact Marineland. You could also start a thread on our Chat Forum to see if others are experiencing this problem. Hope this helps. Steve Allen.>

Automated water changes Dear WWM Crew <Hi Timon, MacL here with you this time.> After 10 years of cichlid and discus keeping I am currently setting up my first reef tank (400 gallon) and after reading Anthony Calfo's excellent Book of Coral Propagation I have been inspired to implement the automated water changing system described in this book. I am planning to feed a continuous drip of fresh sea water, slightly colder than the system water, into the display tank and having the displaced old sea water overflow into the drain from an overflow in the sump. <How exciting for you!> The drawback of this method seems to be that measuring and replacement of evaporated water with a float switch will not work because the water level in the sump will always rise to the height of the overflow.  I am a lazy person by nature and prefer to automate things as much as possible. Do you have any advice on how to automatically top-off the correct amount of fresh water when using this automated water change method? <I think you might be able to set an ro/di unit to put out the same amount (as in rate of speed) as you are putting in and therefore achieve equilibrium.> Much appreciated! Timon

Re: Automated water changes Dear MacL <Hi Tomon> Thanks for the reply. Sorry I am not quite sure I understand what you are suggesting I do. Are you recommending that I leave an RO unit pumping fresh water into my display 24/7 to make up for evaporation? <After looking at multiple options that's the only thing that I could think of to do.  All the other options require being able to use some type of float switch.  So I checked with some makers of RO/di Units and they said you could set the rate of flow on your ro/di units to a very slow rate and have it continuously pumping into the sump at the same rate as what would be dripping into the tank. You would obviously have to set something up in case the electricity turns goes out. Good luck and please let me know what you decide to do. MacL> Thanks Timon

Re: Automated water changes Hi MacL, <Hi Timon> The return from the sump runs through a titanium heat exchanger hooked up to an 18,000 BTU aircon outside, I have been test running for a week now and the temperature of the water has been very stable so no worries there. <Great news, and great news for your evaporation too I think, depends on the humidity of your area as well.> Conductivity controller it is then. I'll let you know if I get good results with it. <I hope it works wonderfully> Thanks for your input. Timon

How stressful and invasive is a water change? I've never been very good at water changes. << Me neither. >> Yeah, I do them, but I have no finesse so they are always so invasive to the animals. Particularly in adding the new water, which never seems to fully mix and has to be added very slowly as a salty, cloudy mixture.<< Okay that is bad.  Probably better to just not do water changes (like me). >> I since went to smaller changes, more frequently. (15g every 2 weeks instead of 30g every month on a 125g) and it seems much less invasive. << Yeah, I'll bet. >> If this is just as effective (and tell me if it is not), could I simply do 2 gallons per day, thus equaling twice the changed water per month, but never being enough at one time to ruffle any feathers? << Well I think it is actually more effective.  Here is why: The purpose of a water change is to make your tank healthier for the fish.  You know, remove waste and replace it with clean water.  However, if you are stressing the fish and making "invasive" water changes like you said, then the added stress level is probably more harmful than the benefit of the water change. >> (or fins, as the case may be) I could do this in 10 min.s per day with minimal intrusion as opposed to spending hours and ultimately pissing off the whole community. Please advise. Thanks, << Less stress is best, then amount of water changed is second. >> -Pat <<  Blundell  >>

Super-Buffered Water? Hi Crew, just want to say thanks for all the great info you are providing.  Unfortunately, I ran into a little problem and am hoping to get some quick advice that I could not easily locate on the website. <That's why I'm here! Ryan with you today> Ok, my problem, I made about 25 of water using and RODI, let it sit for 24 hours, buffered using baking soda and then added salt (instant ocean).  This morning the water is all cloudy and their is white stuff on the side of the garbage can.  From the website it seems I over buffered the water and forced the carbon out of solution. <Not horrible...can you add water to it, and make more make-up water, to even the ratio?> my question is what do I do now, can I still use this water or is it wasted. I was hoping to do my water change today and I don't think I have an alkalinity tester!. Please help, thanks. <You could use it, but it may cloud your display tank temporarily.  I'd either add some water, or dump some out, and then add some more water!  Better safe than sorry when you're talking about thousands in livestock!>   Water Changes <Hi Cheryl, MacL here again.> thanks for the answer....the tank and Koran angel aren't picking on the blue girdled angel so much now...sometimes I think I don't feed them enough I never know how much to feed them...especially since they are larger fish.. <Generally people suggest feeding them a small amount multiple times a day.> No I don't have any corals. The other question I wanted to ask. was... you had said it is best to change 3 gallons of water twice a week. I was wondering if I changed 5-7 gallons every two weeks, and every night change 1/2 - 1 gallon of water. I thought that would be good and would be easier for me. Some other person told me not to change a 1/2 - 1 gallon everyday. I have tried it for a week. <I have to say that seems like a lot more work but if you find it easier. . ., I like to refer to what Anthony Calfo says and I paraphrase "Dilution is the solution"> I also thought it would help slow down any algae growth... I now get algae growth on my glass that I always have to clean off...and my glass is starting to get scratched. <Does your cleaner have sand stuck in it?> I also have mini starfish (I think... multiplied from live rock or sand.) I keep on getting more and more , is that good or bad? <They are multiplying because they have plenty to eat. >They are on the glass when the lights aren't on  and on the live rock. Thanks, Cheryl Cleaning substrate and fish compatibility Hi there. <Steve Allen tonight.> I have a 55 gallon fish only tank and about 100 pounds of live rock. I've been trying to figure out how to vacuum the substrate. Do you hook the hose on to your air pump or what? <No> I tried this but all that happened was it blew air into the water. <Not unexpected. There are a number of ways to vacuum substrate. The cheapest/simplest is with a gravel-cleaning siphon available at any pet store. Just vacuum with water changes. Personally, I use a Magnum 350 canister filter with the micron filter insert. The water goes back into the tank, so I can vacuum to my heart's content without fear of taking out too much water. There are also motorized gravel vacs you can buy that are hand-held and self-contained, but they seem rather wimpy and flimsy to me.> Currently I have 5 fish in my aquarium, 1 Scopas tang <Needs at least a 75G tank to thrive.> ,1 false Percula, 1 orange lined Chromis (he's lost his orange line and is turning brown) <Could be a sign of stress, malnutrition or disease.> a sixline wrasse and a dwarf Hawkfish. I was wondering what else to put in with these guys. <Nothing at this point. You need to figure out what, if anything, is wrong with your Chromis. Any other fish that go in there should not be ones that can/will outgrow the tank.> I was planning on a mated pair of coral beauties <almost impossible to achieve in captivity> ,a valentini puffer <too big> another false Percula <you might be able to get it to pair up with the one you have. Read the clownfish FAQs about this. Do not add some other species of clown.> and a mimic eibli surgeon <I'm guessing you mean  Acanthurus  pyroferus, which grows way too big for your tank and will not get along with your Scopas.>  are these good choices? <Maybe the clown, and/or a single Coral Beauty.> thanks a lot. <Hope this helps.>

Saltwater Changes Hello I've been reading on your site for about 5 days know and finding out some interesting things about reef keeping. One is the water changes. I feel that is important. Second about supplements I've been spending money on something that is useful. Making LFS house payment (lol) I have hard green algae on my glass (not a lot) Is it because of tooooo many supplements that I've been adding << Could be, but I doubt it. >> (not) or could it be microalgae? See I talk it over with the guy at the LFS about changing water twice a week and he suggested that I still need supplements. << You don't need supplements, unless you have something taking them back out.  Before you add anything, test the levels of what you are adding. >> So anyway I'm glad to find your site very very helpful. I'm going to stick with 5% water changes, It makes sense to me. << Water changes make sense to me.  Also, I would recommend either a protein skimmer, or decreased feeding.  The algae growing isn't because of supplements.  What it is caused by is excess nutrients, light, and lack of predation.  So I would cut back on nutrients in the tank, and look for snails and crabs to increase predation. >>I can go on and on about things that I was told but I don't think it is a good thing. I always get second opinions and thirds because I'm so interested in this hobby have been. Thanks again <<  Adam B.  >>

- Reef Tank Water Changes - Thanks for the input. Im glad to come across this web site, Lots of info and also see that I've learned from my mistakes. When doing water changes on 5% twice a week, what other supplements will I need, besides iodine? <Well... if you're changing water that often, you might not even need the iodine.> Im concerned about strontium, I have cal. reactor (Korallin) sweet piece of equipment I must say. <If you're using a calcium reactor and you use quality media you probably won't have to worry about strontium.> I have a 75 gal. reef and want to know if Turboflotor 1000 skimmer is big enough for the reef? <Should be fine.> Im normally change 5gals. a week. Everyone is happy but always up for more input to see a reef thrive. <Just stay on it... Cheers, J -- >

Preparing Water For Water Changes Hello I read Scott's article on changing 5% of water on Wed. and Sun. <Yes, I'm a bit kooky about water changes, but it's a great habit to get into!> Would you still add strontium? I use Instant Ocean. <Personally, I would keep things simple, and not add any additive or supplement unless testing indicates the need to do so. With a frequent water change schedule using a quality salt mix, such as Instant Ocean, you'll be replenishing many of these trace elements that your animals use up. In my opinion, it's better to spend the $$ on salt mix instead of additives!> When doing water changes, how long should you let the water cycle? Thanks <Not really a need to "cycle" water that you're using for water changes. What you need to do is pre-treat the source water (like using R/O water, then buffering as needed), then mix the salt according to manufacturer's instructions, let it sit for a day or so (preferably while aerating it), and it's good to go. Hope this helps! Regards, Scott F> Top-Off Versus Water changes (6/17/04) I just installed a chiller on my 90 gal. saltwater tank (best purchase ever).  <Glad to hear you like it. I spent my $ on central air so both humans and fish can be comfortable in summer here in SLC.> Until now I have been regulating temperature with fans and leaving the tank open.  That practice produced a condition of rapid evaporation (approx. 5 gal/week) <some people lose that in a day or two.>, so I regularly added freshwater (tap treated w/Amquel) throughout the week.  My water has been stable and healthy for 5mos, using this practice. <Have you been testing? No one here would recommend 5 months without a water change.> However, now that I am not evaporating, do I need to manually change water? <You should be anyway. It's the best way to remove nitrogenous wastes, dissolved organics and other evil things while replacing essential trace elements. Evaporation simply removes water molecules, which you then replace with fresh water. Water changes removes bad stuff and salt, so you replace with new salt water. (Read here on WWM for our water change philosophy:   http://www.wetwebmedia.com/scottsh2ochgart.htm )  Personally, I change 10% (25 gallons) every weekend. I make the RO water in a plastic trash can on wheels overnight Friday/Saturday (aerating right from the start with an airstone, which I leave running until I use the water) I buffer it Saturday AM and start a powerhead running in the container. I add the salt Saturday PM and turn on the heater Sunday AM. Sunday evening, I use a powerhead and hose to pump water from the tank down the basement shower drain. I then use the same powerhead and hose to pump water from the container to the tank. Actual time invested is about an hour. Steve Allen.>

How Much Water Should He Change? Hi, <Hey there! Scott F. here today!> I have a 75 gallon saltwater F/O NLR tank with 6 inhabitants.  I read so many conflicting stories about water changes that I want to get your opinion. I know there is water displacement due to rocks and substrate, etc.  Approximately how many ACTUAL  gallons of water would I have in my 75 gallon tank?  Also, what percentage of my water and how often should I change it?    Thanks for your help.  James <Well, James- that's a really good question! Although there are formulas to determine tank capacity based upon dimensions, I am not aware of a formula to accurately determine the amount of water displaced by rocks, etc. I guess the only way to accurately do this would be to have recorded how much water was used to fill the tank after these items were installed. As far as determining how much water to change is concerned, I simply go by "x" percentage of whatever the empty tank capacity is. I figure that, even if the amount changed turns out to be more than 5% (or whatever) of the tank's actual water volume, you're still doing okay. As you may have read on these pages, I really like small, frequent water changes. My personal schedule is two 5% changes per week (Wed and Sun). They work for me! Take care! regards, Scott F> James Hall Water Change 5/24/04 You people are so helpful and courteous! I try not to bother you too much with my quandaries that keep me in a tizzy w/this 220g SW tank, but could use your input. <No bother at all. That is why we are here!> We have a 55g plastic drum that used to contain Greek peppers which we use for water changes. When we got the drum, I bleached it, rinsed it and left it in the sun for several days. <Mine contained cooking sherry. I followed pretty much the same procedure.> Normally, we buy our water pre-mixed from LFS, but I wanted to try mixing it at home using our R/O. Never again; the unit only makes about 2g at a time and it's taken me days to get it filled. <If you are using a unit with it's own holding tank, you should run the line that goes to the tank directly into the barrel. R/O is a slow process.> When I open the drum to add the water, I still smell a pretty strong smell of pickled peppers! My question is, do you think I should use it or just pour it out and get the water in one swoop from the LFS. We've always used this drum to transport the water and never had a problem with the fish. Thank you for advice. Kathy Harper <It is hard to say if it will cause a problem or not. I filled my barrels with waste water from my R/O and washing soda and allowed them to sit overnight. I repeated this process a few times until the smell was mild. After a couple of years use, there is still a very slight smell, but I have not had any problems. Using your own R/O is cheaper and you can proceed with the confidence that you have properly maintained it. You can also always keep water on hand for emergencies. That said, I would subject your barrel to a some more cleaning/rinsing and be sure you are getting the most out of your R/O and go for it! Best Regards. Adam>

System Eliminates Need For Water Changes? Too Good To Be True! Hi all, first time at asking you guys anything, though I've gained tremendous knowledge from your site up to this point. <Glad you've enjoyed the site! We're thrilled to bring it to you each day!> As for my 2 questions. I've seen reference on several forums as to a member named Kdodds that has a setup that "naturally" filters the water, making water changes unnecessary. Has this system ever been outlined? If so, could someone please direct me to a thread, or link to this. If not, would it be possible to outline it, so that it might be a consideration for others? <Not familiar with this individual or theory. To be quite honest, short of an "open" system, which flows water in and out directly from the ocean, I don't think that there is a system that makes water changes unnecessary. Quite frankly, I'm not sure why everyone is seeking a system that eliminates the need for water changes. DO our animals truly benefit? I think not! Let's face it-when we keep fishes in closed systems, water changes are necessary. Period. And they are really not difficult. Not even taking into account the need to properly export organics from the tank water, I question how such a system can replenish and maintain a proper balance of trace elements and minerals in the system. Just adding trace elements is really problematic...How do you know how much of a given element has been used up? And at what rate? If people would spend more time trying to propagate marine animals and less time trying to cook up schemes and additives to avoid water changes, we'd see an even greater diversity of fantastic captive-bred animals in the hobby, and the need to harvest from the ocean would be greatly reduced! That's my two cents on the issue!> Secondly... I live in the southeast, and as most everyone knows by now, Southdown/Yardright/Old Castle sand appears to only be sold in the northeast. At least, it isn't sold anywhere around here. So, I am setting up a 72G All-Glass bowfront, predrilled, with an oceanic sump system below, a Kent Nautilus TE skimmer powered by mag drive pump, and a second Mag Drive to force the return back into the tank. We had the Oceanic sump's optional sectioned glass top custom cut to accommodate the hulking size of the Kent skimmer, hoping to still cut down on salt leaching out of the sump area and cutting down on evaporation. We are planning fish only, and realistically, due to budget constraints, will most likely add no more than 20lbs, 40lbs at the outside most, of live rock, and even this will have to be done across time. We have the tank set up and the sump plumbed, finally... we will be using Instant Ocean salt, and currently have 40 lbs of Aragalive sand and 25lbs of Ultra Reef dolomite. From various reading, I've seen that I should be shooting for a 4-5" sandbed. <If you are seeking denitrification, this is a good depth to start with> 4-4 1/2" will probably be more realistic, in order to not take up so much volume in the tank with substrate alone. Obviously, for that much of a sandbed, I will need additional substrate. As mentioned before, money is always a concern, so, with Southdown and its many aliases being unavailable to me, what, if any, are my options on padding the sandbed size without breaking the bank? I've read in a couple of places that most any cleaned, sanitized play sand could be used, particularly if used as a bottom layer to the other media, but I wanted to run it by the experts first, before making a big mistake that could cost me far more in both money and time to correct. <Well, you want to avoid silica-based sands, as they can fuel tremendous nuisance algae blooms over time. I'd go for an aquarium-specific aragonite sand. Yes, it may be a bit more expensive, but the long-term benefits of this material are worth it.> Thanks, in advance, for any help that you can give. Eric <My pleasure, Eric. Keep in mind that there is no one "right" way to do things. I'm offering opinions and advice based on my experiences, and what I have found to work for me over time. Take any an all advice with a grain of salt, but do turn a very skeptical ear to anyone who tells you that their system or product "eliminates water changes". Better to develop conscientious husbandry habits for your aquarium, instead. Good luck! Regards, Scott F.>

Makin' Changes Good day all, <Michael here, have to be awake in 6 hours :(>  I have automated my water change regimen due to laziness on my 120 gallon reef tank. Every evening I replace roughly 2 gallons of water. Is it better for overall water quality to change a larger quantity of water less frequently or smaller quantity daily (as currently configured)? <Small, frequent water changes are definitely best. I change a quart a day on my 40 gallon reef> Last question: Am I changing the correct amount of water for a 120? <14 gallons a week, 56 gallons a month...sound great>  Thank all of you for your time and dedication. <No problems, we try>  Paul  <M. Maddox>

Not for the Mathematically Declined  >Hi Crew,  >>Hello Simon.  >A special hi to Scott & Marina for persevering with me evolving this fish only tank into something more interesting. I have a hypothetical question to throw at you all. Please don't think I'm daft for asking this but have pondered for many a late night (and many one too many scotches!) on the answer to this one, I have never myself, come up with a satisfactory answer.  >>Right, but we might think you were a bit pissed when you wrote this, eh?  >Here we go... I have a 200gallon tank and I change 10% of the total water volume (for example) every seven days routinely.  >>Right.  >My question is this. If I were to add (hypothetically) a 200gallon sump to this tank (which is just a sump for the addition of water volume) and I remained with exactly the same bio-load in the display tank, Would it be correct to then change 5% of the total water volume each seven days? (which would obviously be the same amount of water as before) or would it be correct to still change 10% (i.e. double the amount) of total water volume?  >>Correct vs. incorrect? How about making this one a multiple choice question?  >A pint of good English beer to the one with the best answer !.... ;-)  >>Oo.. if only I liked beer.. if only I drank!  >I thank you all again for your fantastic help and guidance through this extraordinary minefield I seem to have got myself into !! Cheers, Simon  >>Well, Simon, I've thought this through, and it *would* seem that, logically, you ought only change the 5%. However, something tells me that, mathematically speaking, this is likely not the case. It would have to do with how much you're actually diluting the end results of the life processes of the livestock, and 10% isn't much in the first place. 5% is even less. So, whilst my beau has a minor in math, I am, I'm afraid, quite mathematically declined - even have trouble using a calculator. I'm very good with maps and words, though! Oh.. you probably want an answer. Well, my friend, my gut says keep changing 10% (though my experience says 30% <wink>), no matter the difference in water volume. I am unable to explain why. Marina

Testing my Inabilities >Thanks again Marina, >>Hee.. I took your question to the math minor, and he said (and I quote - remember, he's a reef keeper), "Changing 5% would work out just fine as long as the bioload doesn't change." I tried to argue that the dilution ratio *must* be changed, but he said that as long as the volume the fishes are swimming in they should be producing a relatively stable amount of waste, therefore, that variable isn't so variable. <shrug> Long story short, he says your original assumption is mathematically correct. >Not bad ! Guess I'll have to have your beer then!!.. >>Please do enjoy the pint for me. My mother says, "Make it a Guinness, BRILLIANT!" >For the record I too have the "gut feeling" same as you do regarding the actual amount of water to be changed. >>A rather visceral exchange. >Anyways, down to the question. The 200gallon tank + 10% water change is hypothetical. If it were purely Mathematical then I think I would be ok (Many moons ago I received a bachelors degree in pure Mathematics......Still to this day I do not know why I did that though, I hate Maths (or math as you rebels would say) with a passion.) >>Yet, we need math, how many mathS can there be, anyway? You should see my oldest boy trying to convey quantum theory to his mother, I can NOT wrap my mind around some of the stuff he's coming out with. >Anyways back to the question again. If we remove from the equation the Mathematical variable (dilution of the end result of the life processes) then, would doubling the tank volume of water mean I would have to change more (double the) water on a regular basis? >>Apparently not. As long as the fishes are not swimming about more, and assuming they've already achieved final adult size. >There is a reason for asking this question as I evolve my display set-up. I am going to add a sump (was to be a very large sump to contain all the water treatment paraphernalia and also for more stability in the water itself but if this means I will have to effectively double my water changes, then I will think again. >>I don't think that will necessarily be the case.  >One more quickie?.....oops! >>You cheeky monkey.. ;) >The next stage for me is to build a refugium of both fine sand and coarser sand (both separate from each other) for pod reproduction and Macro algae's (NNR) respectfully). >>Excellent!  >Is there a benefit in doing this in a tank containing mainly small fish, shrimps, BTA, etc? Or should I just stick to NNR reduction & forget about pod production? >>Oh no! The pod production is (in my opinion at least) *always* of benefit, especially if you ever wish to keep fussy fish that pick about the rockwork. It is technically those cryptic species (not sure if that's the correct word, but the root is "crypt") that make a 'refugium' the refuge that it is. >Sorry for all the questions but I've maid so many mistakes in the past I wish to minimize these this time round. >>Again, no worries, this has gotten to be fun.  >Many, many thanks to you all. Simon. >>Welcome to it, Simon. Marina

My Reef Tank/hazy water/dead feather duster 4/1/04 Hello Folks Since I started changing water weekly in both my reef and fish tank and my son reports since he started changing water weekly our tanks are a little hazy. The water is never crystal clear anymore but a little hazy.  Do you know why? <Could be many reasons.  Newly mixed artificial sea water (ASW) should be allowed to "age" for at least 24 hours with some kind of agitation or aeration (powerheads or airstones work well).  I would also check the calcium and alkalinity and pH of your tanks and your ASW.  If any of these parameters is unusually high, it could be causing some precipitation to occur, which would explain your haziness.> Also what makes a feather duster leave its tube? I found my feather duster dead on the bottom of the tank.  Why?  Thanks, Kirt <I need lots more info here.  If it was a new addition, it may have died from shipping stress.  If you have had it for a while it is likely a water quality issue.  I will need to know salinity, pH, Nitrate and Alkalinity.  Also, a description of your system, filtration, water movement and maintenance routine would help.  Best Regards.  Adam> Water Changes & ORP To WWM Crew - This is an amazing site.  Thanks for all the wonderful and free advice.   <always welcome my friend> My question is:  twice a week I make water changes on my 125 gallon salt tank (1 ten gallon change on Wednesday and 1 five gallon change on Sunday) using buffered DI water that has aged 4 days.  Every single time I do this my ORP immediately (within minutes) drops almost exactly 150 points from 370-380 to 220-230.  This happens with both the five and ten gallon water changes.   <this is quite normal... it should recover within 24 hours> The ORP probe is at the opposite end of the tank from the sump return in which I add the new water - so it makes the rapid change even more puzzling.  The ORP gradually returns to normal over the next 24-36 hours.  The only creature bothered by this is of course me.  It doesn't seem to make any sense.   <understood... but it is normal/natural. The new water has not been exposed to great surface areas (turned over in low long tank) nor vigorously aerated as with a skimmer... and add to that the water change stirring up sediments that lower ORP, etc> Just to satisfy my curiosity - what is the mechanism or chemical reaction that causes this?  (I just bought an ORP probe a couple of months back and am no longer blissfully ignorant of the variations in ORP.)  Thanks! Scott <good thinking/curiousity... but no worries. Kudos. Anthony>

Using Buffer 2/16/04 Anthony----will do water changes ,first one in the morning, I will test Ph in the tank first, suppose its 8.05 again, what should I set my buffer for ,for my water change? 8.1 maybe 8.2 ? I don't want to set my buffer to high or I will be doing what I did before. Right?  Charlie <Charlie... you simply need to use and obey your test kits. Add enough buffer to your raw after as it takes to get a strong pH/ALK reading in t he final mix (target 8.4-8.6). Really is that simple. Anthony. You may need to buy and read a good book too my friend. Answers these fundamentals nicely: "New Marine Aquarium" by Mike Paletta... Bobs CMA... or the first half of my BOCP1 (all reef fundamentals). Anthony>

10 in depth of water 2/12/04 I have s quick question, If my tank is only 10in deep can I use SO fluorescents (of the appropriate temp), changed regularly, in conjunction with T5's to light Euphyllia, Sarcophyton, Heliofungia, Pachyclavularia, Plerogyra, Catalaphyllia, Trachyphyllia? Could I possibly go to 12 in depth. Also, I will have an 11 inch sand base under them, and of course live rock in the tank so some corals could be placed higher if needs be. All of the corals you listed will tolerate SO fluorescents with no problem, even if you increase the depth a bit.  I would recommend that you try to get four lamps per foot of tank width and cover the entire length (four lamps over a 55 or six over a 75, for example).> Is the sand bed to deep? In the main tank I don't want the sand dissolving under the coral and lowering them, could you recommend a sugar fine sand that doesn't dissolve. <I don't think 11" of sand is too deep, but after about 6" I don't think you will reap much additional benefit.  You also have to take into account the tradeoff of diminished water volume.  If the only goal is to get the corals closer to the light, then I wouldn't bother.  Any aragonite based sand will dissolve.  Silica sand will not dissolve, but it's use is controversial.> I will be using Aragamax in the sump to help with buffing as well as a calcium reactor. Finally, water changes are very important and I do them frequently but as many people know what ever you spend on your equipment initially pales in comparison to what you will ultimately spend in upkeep. I am trying to set up a system that meets all the animals needs but is cost effective over time. Since I do 25% water changes every week the expense of salt is killing me, any help in getting less expensive salt that will get the job done. <I too believe in the importance of water changes, but unless you have tremendous input, 25% per month should be more than OK.  I can often find IO brand salt for about $10 per bag and less than $40 per 200gal bucket.  Getting any brand for any less than that will be a challenge.> I know many people say just have better filtration, but I have an excellent protein skimmer etc., low contaminants, I have just found water changes help a lot, maybe its diffusing all the things we can't test for like chemical warfare etc...I just don't want to stop using them as they have worked for me.  What do coral farmers do about the huge amount of salt they need for their systems? Thank you Greg <Again, you have my agreement about the benefit, but you may get 90% of the benefit with half of the water changes.  Small amounts of regularly changed carbon will help too.  Any business with large systems simply buys salt in large quantities.  Since a large part of the cost is freight, buying in pallet quantities saves cost.  Also, some large commercial facilities re-use water, sending "used" water from SPS systems to soft coral, fish only or live rock systems for example.  Hope this helps.  Adam>

Water top off hello crew! <Howdy!> I have done a lot of research on water top offs using water from a ro/di. my question is can you just use the pure ro/di water to top off? or does that water need to have anything added to it? <I would add some sort of buffer for the ph.  And if your tank is low on calcium, calcium>also the water will be aside my tank in a 5-10 gal container how long can it sit there without any circulation? <It would be best if you could run a small air pump or airstone in there, but you should be just fine as Long as it has a lid on it. Cody> thanks for any help.....ed When It's Time To Change (Water Changes) Thanks again.  I am now at this new tank for one week.  Loving it! <Excellent!> Anyhow,  I'm wondering how you accomplish changing water so frequently.  5% twice a week is a chore for sure. <Honestly, it's not that big a deal, once you get a "system" going. It becomes a habit pretty quickly.> I was thinking 25 to 40 gallons a week. I thought of using a trash can and mixing it in there.  I read a bunch and am somewhat confused. <Hey- just about any water change regimen is better than none at all. My "52XW" regimen is just one of the many ways you can complete water changes...> I was thinking just bleeding off a measured 25 - 40 (not sure what the salt cost is yet) gallons then just adding it to my sump and pumping it back in.....is this ok? <Sure, as long as the water being added is of the same specific gravity and temperature as the water in the display> If I use tap water do I  have to add chemicals to it? <Really depends on your source water. Personally, I use an RO/DI unit to get the most pure water possible (yep- ANOTHER thing to buy...), but many hobbyists can use their tap water (when properly prepped) with no problems> I'm going to leave it for a week at a time.  Use a Rio to circulate it.  I'll heat it to 78 degrees then do the water change every Sunday.  Do I need to add baking soda to the water? If so, how much?  What order do you do all of these things?  I'm so darn confused! Thanks again. <Well, all of these questions are covered in great detail in the FAQs and articles on the WWM site, so do a bit more reading, and I'm sure that you'll get this figured out pretty quickly! Regards, Scott F> - Going Without Water Changes - Greetings to the WWM crew.  On one of the fish forums I frequent there is a lot of talk about how the folks don't do water changes on their marine systems. They state the use of deep sand beds and protein skimmers eliminate the issue of nitrate build up and make water changes unnecessary. <Check back in with them in a year or two...> For me, that just doesn't seem like good maintenance practices. <Me either... consider not flushing your toilet, ever...> If you aren't dosing the tank with additives (and don't want to start), shouldn't the use of fresh synthetic sea water be used to maintain water quality? <For a myriad of reasons, yes.> I mean, there must be more to water quality than just ammonia, nitrite and nitrate. <Absolutely.> With corals and fish using these trace elements from your saltwater, wouldn't the addition of fresh saltwater be necessary? <Yes.> Wouldn't the lack of these minerals cause some sort of deficiency in your tank inhabitants' health? <Certainly.> Top off water wouldn't be able to provide an adequate level of these minerals would it? <No... we are in complete agreement.> I guess I'm just a little confused as to the extent of what you can count on DSB to do for your marine system when you aren't dosing trace elements or doing water changes. <I wouldn't count on it much. Not sure what the fascination with zero-maintenance tanks is... I'm always fond of the following metaphor: consider that the oceans of the world cover 2/3 of the planet. Consider now the size of your fishtank in comparison... smaller than a grain of sand. How does/should one maintain the stability and water quality of the oceans? <Water changes are one of your best friends.> I would appreciate your opinion on the matter. <The folks who choose not to change their water and instead rely on their laziness and their closed microcosm will regret their decision in time.> Many thanks,  Oleta <Cheers, J -- >

Water Change Challenge I have a 90 gal reef with 20 gal sump. I do a ten gal H20 change two times a week. LFS said that was too much. What are your recommendations? Thanks <Well, I'm a water change junkie, myself! I am a big fan of frequent small water changes.  I suppose that the LFS felt that substantial water changes would be too disruptive? I would go with two 5% changes a week. On the other hand, if you are using water that is exactly like that in your main system, and you are careful in your other husbandry, there is not too much harm that can come from substantial water changes! Just let the reactions and condition of your animals guide you. Any water change, done correctly, is a good thing! Keep up the good work! Regards, Scott F.>

Starting marine water changes hello I have had my marine aquarium for 4 months I was just wondering when to do the first water change to it? <I would start doing water changes, help replace the minerals and nutrient loss.> Also what is the SG, temperature, KH and PH suppose to be ?????????? <WetWebMedia has a phenomenal FAQ area for you on marine tanks.  Please take a look at it and learn all that you can! http://www.wetwebmedia.com/marine/setup/index.htm Hope that helps! -Magnus>

Water Change Maniacs - Unite! Hi Scott <Hi there!> I have another one for you on water changes? <Sure- one of my favorite topics...heh, heh!> I was thinking of doing small weekly water changes or either doing a water change every 2 weeks. <Well, people who read my responses on WWM and suffer with me in person know that I am a huge proponent of a twice-weekly water changes (2- 5% changes per week)...> I have a big drum that can hold +/- 84 litres, is it possible to mix this entire drum with salt and keep in running in my garage.  If I do weekly water changes I am looking at changing 24 litres a week and if I do water changes every second week I am looking at doing +/- 36 litres. It would be a lot easier to just keep the water in my garage instead of having to mix it each time I do a water change. <I can relate> If I do it this way I would probably only have to mix the water +/- once a month. I can keep the water aerated and mixing my means of two powerheads, would this suffice or would you rather advise mixing the water fresh over night each time? <I prefer to mix it as I go, but I see nothing wrong with your idea of mixing it up in larger quantities ahead of time> I just wanna simplify the entire process and have my hands in the tank as little as possible and rather enjoy the hobby instead of it becoming to taxing on my time. <Nothing wrong with that. Although, I suspect that you will find that having your hands in the tank more often is not such a bad thing!> I must say mixing the water over night once a week and doing a water change ain't too hectic but it does take time. <Yep- but the benefits of such small, frequent water changes are so many that you will definitely want to perform them...> Thanks Ziad <My pleasure! Regards, Scott F>

Water Change for Xmas Hey guys and gals <Morning! Ryan Bowen with you today> Two more days and I think I will have your book. <I'll assume you're referring to my slightly more distinguished colleagues...  ;)  > I think it is under the tree already. I have been reading your web site and FAQ's about water changes and would like your opinions on how to prepare the water. any advice, whether it is too much or too little, would be appreciated. <Surely> The way I am doing it was not the best but here is what I am planning in the future. I will use tap water that is filtered through a PUR water filter and than add AmQuel and a little Stress Coat also Kent DKH and pH Buffer (This is what I am doing now with little time in between mixing the water and adding it to the tank). RO is not in the budget right now. <Hmm...add up those additives!  RO units start around $125.00, a fraction of what you'll spend on additives, replacement PUR filters, etc. in a year>  My water has always tested good at home and at the LFS. After reading your articles and FAQ's I think I can improve many of my practices and I want to start with this one. <Yes, I would agree.  A simple, comparatively cheap way to keep your tank healthy and vibrant.> I have a 55 Gallon FOWLR and a 10 gal mini reef. Right now I also have a 10 gallon tank running with some LR and Foxface waiting for his tail to grow back. <Glad to see that you quarantine> I am running an Emperor 280 with fiber in the filter and treating with Melafix. I am thinking of removing the rock, fish (Back to LFS) and Emperor and water and replacing it with new saltwater and a small power head and using this for water changes in the other tanks or would it be better to buy a new tank? <Any large sturdy plastic container will do.  I use a 25 gallon IKEA garbage bin!> I would let the water cure for a week. <OK, but the water reaches a chemically stable point after about 24 hours...the benefits of the next 6 days are slim.> I would like to get on a schedule of 5 gallons/1 gallon a week. Too much or too little? <The right amount> Also should I let the top off fresh water cure before adding it to the tank? <No, unless there is a serious change in temperature.> This water I add directly to tank with AmQuel and PUR filtered water. Thanks.  Have a Merry Christmas!  Pat <Let's just hope there are no frags cooking under my tree as we speak!  Happy Holidays, and enjoy your next read! Ryan>

Water Change Water Change >Good Morning, >>And to you as well. >I love reading your website and have benefited so much from it.  Thanks for your time and sharing your experience with us. >>It's our collective pleasure. >My question is a simple one.  Perhaps it doesn't matter, but I wanted to be sure.  I have a 20 gal tank w/ 30 lbs. of live rock.  I do a 1-2 gallon water change per week (depending on whether I'm vacuuming or not).  My question involves the bin where I mix my salt water (my reserve).   >>Righty-oh, lay it on me. >I use a 5 gallon round Gatorade container with a handy spigot at the bottom. I mix the salt water from a couple of jugs of RO that I have slowly brought up to 8.2 pH.  In the reserve tank, I have an air stone and a heater (I only heat several hours prior to doing a water change).  So finally my question.  Because this is a 5 gallon container, it takes about a month for me to empty it doing 4 water changes.  Is this too long to keep water without a filtration system?   >>No, but you do want to keep it aerated. >If so, what type should I implement, or should I just mix enough for a couple of water changes at a time?  Thanks, Sher H. >>Just keep a small air pump handy, plug it in with an air stone dropped into the bottom of the jug for a day before you do the w/c.  Once you get down to that last gallon, this isn't quite as necessary.  If you see salt creep on the inside, then mix it back down, likely the salinity will drop if you don't.  Marina

- Top-off Water - Hi, I checked the KH of the DI water from my tap water filter and the reading showed high. <Somebody needs to change their DI resin!!!> I checked the water before the filter and it showed the same. <Yep, that cartridge is spent. They're color change, so you need to stay on top of making sure it's in good shape and tossing it before it gets within a few inches of the top.> Unfortunately my Marine Aquariums Test Lab kit only has a scale of low - normal -high, so I don't know what that translates into. <Although that kit is effectively useless for your aquarium, it's a nice heads up here.> I have been adding high alkalinity, low PH top water up till now. Do I need to buffer the top off water, if so how much baking soda per gallon ? <Hmmm, change your DI cartridge, and skip the buffer. Get a real KH test (that gives readings in dKH or alk) and maintain it in the tank. If your water is pure, this should work out just fine.> I noticed in reading the FAQs that there is much talk of aerating the top off water, I have never done this...is it necessary? <If there's excess CO2 (which could very well be the problem here), good gas exchange via aeration or using a powerhead would remove much of that.> Also, I have never monitored my calcium level since no one has told me it was necessary, I only have a 55 gallon and 10 gallon fish only tanks maybe a crab or two with 9 pounds of live rock at the moment. If calcium is a factor, what should it be at? <Around 400ppm, it is very important to monitor your KH as well, as they effect each other. Do a search on reefs.org for articles by Randy Holmes-Farley, he's written some pretty awesome articles on just this subject.> I have had bad luck with inverts such as chocolate chip star fish so far, and I am not sure why? All normal tests show good. <Could be acclimation, poor quality livestock, faulty kits (the cheapest kits I would ever use are the Seatest and Fastest line). That would be the subject for another email so we could figure out what happened..> I had no idea how complex this hobby was going to be when I got into it 2 years ago, the main problem is that everyone and books all have a different opinion, and some lessons must be learned the hard way. <Alas... All I can say is keep on researching and buy some good books! Good luck! -Kevin> Thank You Randy

-Top off water driving pH down?- Hi, In a recent water check I was told that my top off water is low in pH. It is resin filtered from a well. I have to add a lot because of evaporation, and it was suggested that I might be driving the pH down with the top offs. My current PH is about 8.0 - 8.1, I hit it with buffer twice and haven't been able to get it to 8.2. <What's your carbonate hardness at? Also, having a pH from 8.0 to 8.1 isn't the end of the world and is perfectly acceptable if your carbonate hardness is in the correct range.> How can I adjust the pH in the top off water, and what should it be? <That would depend. If the resin that filters the well water takes out only a few things and leaves most of the dissolved stuff intact, I would suspect that it would be around neutral. If you use deionized water, the pH could be any given value, and would change instantaneously should any buffers be added. I prefer to add straight RO/DI water and maintain the KH via calcium and alkalinity additives.> I used buffer in the top off water, but it left a lot of white powder residue, but it did adjust it to about 8.0 or so. <No worries. Check the KH of your aquarium, if it's anywhere between 9-12, 8.0-8.1 is the best your going to do for pH if the problem isn't excess dissolved CO2. If your KH is low, add some buffer to raise it to the appropriate level> I heard you could use just baking Soda. <That's true, but check your KH first. Good luck! -Kevin> Thank You, Randy

- pH Level of Top Off Water in a Marine Aquarium - Hi, I am probably not going to be talking to the same person, but I wanted to put in a small follow up. <You win the prize, this is not the same person - JasonC here rather than Kevin.> I starting running an airstone in my water bucket and the pH change in 12 or so hours was major. It went from below the scale to around 8.0. <Interesting.> The DI kit that I bought that connects to the tap went dark all the way to about 1/2 inch from the top the first time I used it. <Mmm... double check you are connected to the proper end of that cartridge.> I thought this was strange, but at the same time I doubted that the well water could possibly be that bad. <You never know.> It has no odor and I have seen bad well water. <Bad well water can be odorless.> I checked the filter's output for nitrates since that was the reason I bought it in the first place (I was getting around 40 out of the tap). I decided that the color change was useless since it went that far on the first few gallons. I am seriously considering an R/O system, any suggestions on the best one for under $200? <Consider a bare-bones RO unit... that should get you in under that door.> I am not rolling in money at the moment. Oh, also....What is the best dKH test kit for general purposes (your view), <Salifert, SeaTest, Sera.> Mine is apparently junk and claims to an ALK test. <Well, from your previous email you indicated that your test only measured low/medium/high - that's really the largest problem with your current test. Rather, a test with a numerical result on a standard scale like dKH, meql/L, or ppm.> It isn't much help. <It is of some help but you can do better.> Thanks again Randy <Cheers, J -- >

Re: water quality Another question. I got a vacuum for the gravel, do I need to vacuum the "whole" tank at once or do it in shifts weekly or what? It doesn't really specify on the box from the vacuum./ Thanks again JJ <Mmm, time to refer you to WWM. Please see here: http://www.wetwebmedia.com/FWSubWebIndex/fwh2ochgs.htm and the FAQs (linked, in blue, at top) beyond. Bob Fenner> The Five Percent Solution (Frequent Small Water Changes) Hello All, <Hi there! Scott F. with you today!> Thanks for such a great site.  I have a 75 Gallon FOWLR with 2 false perculas, 3 green Chromis, a yellow tail damsel, and a Firefish. I plan on adding a couple of softies and maybe another fish or 2.  My water quality is fine for now, but as I add bioload, I know I will need to watch for nitrates and phosphates.  My question is would 2- 5 gallon changes be better than 1 10 gallon change a week for nutrient export? Thanks, Jeff <Ahh- good question. I have a very strong opinion on this. Mathematical algorithms aside, I feel that two smaller water changes would be more effective than one larger one, for the simple reason that you are removing organics from the water before they have a chance to build up. the "momentum" that you will achieve from frequent small water changes and the dilution of nutrients that they achieve will create a noticeable difference in water quality in the long-term. Not to mention, the process keeps the salt mix manufacturers happy, too! (I think I am a majority shareholder in Tropic Marin!) Give the small water changes a try. I'm sure that you'll like the results- and they really are not that hard to perform...Regards, Scott F.>

Snail Tale... Hi Folks, <Hi there! Scott F. here today!> I have a 350l reef containing 50kg of live rock and approximately 1 inch of coral sand. I know ideally I should have little or no substrate at all with live rock, but I do like the aesthetics of sand. <Actually, there is nothing wrong with a deep sand bed and live rock, as long as there is sufficient open space...I always like to recommend 1/2 inch or less, or three inches or more of sand. One inch is too shallow to be foster full denitrification processes, but too deep to be fully aerobic...better to increase/decrease for long term success. However, with sufficient burrowing snails, you may be able to get away with this...> I was considering introducing Nassarius snails into the reef to (a) consume debris and (b) turn over the sand. My local supplier recommends 50 of these snails for my tank. My first question is do you agree with the stocking level he has recommended? <It's a lot for my personal tastes, but certainly not too much. These snails do a great job as detritivores> Secondly, I "Hoover" the substrate during my weekly water changes to remove debris, will the suction action harm the snails? <Well, not "harm" them physically, but it will remove much of the food that they consume-mainly detritus. If you're going to utilize a substantial population of these snails, I'd avoid heavy cleaning of the sand bed> Thank you very much for your help. Andrew Senior <My pleasure, Andrew! Good luck! Regards, Scott F>

Gravel vacuuming, feeding Centropyge Hi, I have 2 non-related questions.  First, this is my first attempt at saltwater fishkeeping (about 8 months now).  I have crushed coral for substrate.<that is what I use>  I would like to know how deep I should clean the substrate.<I clean mine every time I do a water change, which is every 2 weeks> Do I just vacuum the surface or do I go deeper?<I vacuum most of the substrate in my aquarium. not very thoroughly, just spots where I see some detritus or crud lol>  The substrate is about 1 1/2 inches deep.  Also, I have had a coral beauty angel for about a week now.  He has yet to come to the top to eat with the other fish.<angelfish from the genus Centropyge generally eat foodstuff off of the liverock for about a month and then they begin to come and eat from the surface..> Instead he just seems to pick off the bottom (maybe the diatoms?)<or leftover food??>  Is this normal for this type of fish?<yes, it is exactly what my golden pygmy did and still does but now he comes to the top of the aquarium and eats right out of my hand!!! be patient my friend, IanB>   Thanks for your help, James

- Losing Fish, Follow-up - Hi But I thought with Chemipure I would not need to replace the saltwater for up to five year? <I should hope not... I've never trusted anything that promises 'no water changes' and there's no filter media I am aware of that would last five years. To keep your fish healthy, you simply must do regular small water changes, otherwise your fish end up living in their own filth. Five percent a week or 10% every two weeks is a good interval for water changes, but it's not wise to wait much more than that.> By the way, I have check my PH level, it is at 8, so it is at a healthy level. <Uhh... pH should be in the range of 8.2-8.4 so 8.0 is actually lower than it should be.> I mentioned my tank as 2ft tank not 2ft long apologize if I mislead you. <I still not sure I follow - what are the dimensions of your tank?> Cheers Terence <Cheers, J -- >

Frequent Small Water Changes And Other Fun Stuff! Folks, <Hi there! Scott F. with you today!> Sorry if you've got this twice, I seem to be having e-mail problems. <Not a problem...Those new-fangled email things are always a pain...LOL> My 150 gallon (incl sump, main tank 125) reef will be up and running soon. I  hope), after lots of planning, and help from WWM crew (thanks). <Cool! Now the fun REALLY begins!> I'm aiming  on a 15 gallon water change a week. Does it make much difference if this is  15 gallons at once, or 5 gallons every couple of days or so. I could manage  one change of 15 galls. but it would be easier for me to do smaller changes  more frequently, as heating and mixing 15 gallons at once is a bit difficult in the space I have for my 'hobby stuff'. <Well, when it comes to water changes, you're certainly talkin' to the right fish nerd! I love the 10% weekly water change idea. I think that two 5% changes on say, Wednesday and Sunday would be perfect! By breaking up the changes into two days, you're really helping to dilute excess organics before they have a chance to accumulate. And, they are very easy to accomplish...> The tank will have 250W halides and I've been told that for a reef system I need to remove the sliding cover glasses. So plenty of evaporation, plenty of Kalk. However, occasionally I have to be away from home for up to two  weeks. When this happens will putting the glasses back (to reduce the 'top  up' requirements on a long suffering family) harm the corals & inverts (SPS & clams in eventually)? <Should not be a problem in a well-managed tank. At some point, you may want to consider a calcium reactor for alkalinity and calcium supplementation...> An auto - top up is on the cards, but even this might not be enough for a two week absence. <There are plenty of hobbyists that use auto top off systems without incident, but I know three individuals that had absolute disasters with them (one which caused almost $100,000 of water damage!), so they scare the hell out of me! Find a design that works, build it well, and check it out constantly...> Final question ...my overflow chamber and first sump compartment came full  of bio balls. I've removed these but suspect the overflow will now be very  noisy. If I fill the 'gap' with small pieces of living rock am I just  swapping one wet / dry nitrate factory for another. <More or less, yes!> If so, any suggestions  for noise reduction. Following a thread on WWM I looked at Durso standpipes. <That was my suggestion! They really are quiet...> However I have the DIY skills of a hippo who has just won the annual  Serengeti 'Mr. Clumsy Hippo' contest, so found the construction (or fitting,  or even the concept), beyond me! This is not false modesty ... The sight of  me with a drill and screwdriver in hand can reduce my family to tears. <Ah- you've found a kindred spirit in me! LOL. In that vein, you can actually order the standpipes custom made by the man himself, Rich Durso. They are really easy to build, but Rich can do it for you. I don't happen to have the URL of his website saved, but you can do a search on the net under his name and locate his site...> If I decide to go for FOWLR what would you recommend as good shoaling fish, preferably brightly coloured, not too big, and quite peaceful, easy to feed. (Oh yes, and the moon on a stick please) <Well, I can't get you the moon, but...I like green Chromis, myself. A great fish to keep in a small group. You could also consider a small group of Royal grammas. What- Royal Grammas? Yep...They won't school, but they can be kept in small groups if you give them enough caves and places to hide in. You might actually witness spawning behavior in such a group...Another choice would be Cardinalfish, which are available in many species and colors...Interesting fishes that make a fine group display...> Thanks yet again. Brian <Hope this helps! Good luck! Regards, Scott F>

- Water Changes - Folks, <Howdy.> My 150 gallon (incl sump, main tank 125) reef will be up and running soon (I hope), after lots of planning, and help from WWM crew (thanks). I'm aiming on a 15 gallon water change a week. Does it make much difference if this is 15 gallons at once, or 5 gallons every couple of days or so. I could manage one change of 15 galls. But it would be easier for me to do smaller changes more frequently, as heating and mixing 15 gallons at once is a bit difficult in the space I have for my 'hobby stuff'. <You'd be better of with the one, larger change... if you can make space for a [new, plastic] garbage can, this would be sufficient to prepare and store plenty of new mix water.> The tank will have 250W halides and I've been told that for a reef system I need to remove the sliding cover glasses. <No, please don't. These provide a margin of safety and also UV protection.> So plenty of evaporation, plenty of Kalk. However occasionally I have to be away from home for up to two weeks. When this happens will putting the glasses back (to reduce the 'top up' requirements on a long suffering family) harm the corals & inverts (SPS & clams in eventually)? An auto - top up is on the cards, but even this might not be enough for a two week absence. <I don't even think it will be enough for a week.> Final question ...my overflow chamber and first sump compartment came full of bio balls. I've removed these but suspect the overflow will now be very noisy. If I fill the 'gap' with small pieces of living rock am I just swapping one wet / dry nitrate factory for another. <In essence, yes, but bioballs in the overflow compartment will be submerged so they won't function like a wet/dry, so these are safe to leave in place.> If so, any suggestions for noise reduction. <Alter the input so that the water doesn't flow out from so high... closer or even in the water in the sump.> Following a thread on WWM I looked at Durso standpipes. However I have the DIY skills of a hippo who has just won the annual Serengeti 'Mr. Clumsy Hippo' contest, so found the construction (or fitting, or even the concept), beyond me! This is not false modesty ... the sight of me with a drill and screwdriver in hand can reduce my family to tears. <Durso stand pipes can be purchased directly from Richard Durso: http://www.rl180reef.com/pages/standpipe/standpipe_frame.htm > Thanks yet again. Brian <Cheers, J -- >

Water changes 9/4/03 Anthony- What % of water can be change in a reef tank every day.                RGibson <there is no minimum % if it is done safely. Some wholesalers with heavy fish loads do 100% daily. For very good aquarium health, however, 10-20% daily would be very fine. Anthony>

Water Treatment I have just found this site and I am grateful for the archives in Q&A type format. Thanks for all the great info. <Thank you for the kind words! We enjoy bringing it to you! Scott F. with you today!> I live in the United Arab Emirates, in an apartment, with limited space. It would be very handy for me to use bottled water (5 gal. water cooler style) from a local supplier. I have obtained a water quality report (see below). They claim that the water undergoes a RO process. Would you suggest that I buy an additional unit (something cheap and portable like the product shown here --> http://www.drsfostersmith.com/product/prod_Display.cfm?siteid=6  http://www.drsfostersmith.com/product/prod_Display.cfm?siteid=6&pCatId=4484&pCatId=4484   and put the water through another processing for my new marine tank under construction that will house fish and possibly some corals? Would the fact that I plan on regular water changes impact this decision? Thanks. Water Product Specification * pH  @ 25 degrees C = 7.8 8.2 * Conductivity @ 25 degrees C (|uS/cm)  =  95 - 105 * TDS @ 25 degrees C (mg/l)  = 95 - 105 * Total Hardness as CaCo3 (mg/l) =  35 - 45 * Total Alkalinity to pH 4.4 (mg/l) =  45 - 55 * Calcium (mg/l) = 15-20 * Magnesium (mg/l) =  03 - 05 * Sodium (mg/l) =  25 - 35 * Potassium (mg/l) =  0.5 - 0.7 * Bicarbonate (mg/l) =  55 - 65 * Chloride (mg/l) =  20 - 30 * Sulphate (mg/l) =  05 - 10 * Fluoride (mg/l)  =  0.45 - 0.55 * Total & free Chlorine (mg/l)  =  Nil * Turbidity (NTU) =  Nil * Taste & Odor  = Acceptable/Good Carolyn Munson <Well, Carolyn- your water looks to be pretty good, however, I'd highly recommend further treatment via an RO/DI unit. This is the best way to obtain consistent, high quality water. Hope this helps! Regards, Scott F>

A Little Change Is Good- What About A Lot? (Big Water Changes) Dear on-staff WWM water change guru: <Scott F. on call tonight> I've become somewhat suspicious at the rainbow of expensive marine supplements available, and the claims each make about not only the benefits of using their product over others', but the necessity of using them, period. <Well worth questioning> Running some numbers, I've found that it would be much cheaper to up the water % I change every week from about 15% to 25% and quit using supplements. Even going up to 50% a week would be cheaper, which for me would be about 50 gallons per change. <Ok...I am a big water change fanatic, but I think I'd limit them to 10 percent per week, 15-25 percent max. If it were me, I agree with you that it's a better idea to utilize water changes to "replenish" trace elements, etc., but 50% water changes would be a rather unnecessary extravagance, IMO. I wonder how much supplementation that you'd use in a 100 gallon tank to make changing 50 gallons of water a practical solution!> The idea here, of course, is to bring in all needed major & trace substances during these changes, in addition to the benefit of flushing away the bad nitrogen guys and what have you. I got this idea from my LFS, who perform weekly 90% changes on some of their reef tanks and don't bother with any supplementation or even skimming. <Again, I love water changes, but I have to question that philosophy. Even public aquariums with semi-open systems utilize protein skimming...It's your first line of defense for many potential water problems. However, the concept of massive water changes is interesting...But there are other potential problems, such as the trauma to animals, if performed in a lax matter> Of course, reading through the literature such as Fenner's TCMA, advice is given against doing too big of a water change due to the shock it may incur on your critters...and the loss of some beneficial stuff, like calming pheromones. <I agree with the issue of potential shock, as well, if parameters are not consistent> I'd like to get some feedback on this topic (25%-50% weekly changes), and perhaps some more info. on what negative things can happen from this? I assume that I will keep using a high-quality mix that gets nailed every time in terms of matching the tank's salinity, pH and temp....and that the fresh mixing water is as pure as possible. Thanks so much! SLC <Well, my concerns are mainly based upon the practicality and affordability of such massive changes...It's a neat concept. As Anthony quotes "dilution is the solution to pollution"! I like the idea, in theory-I just cannot imagine the average hobbyist bearing the expense. If you can afford it- and if you can do it right (keeping things stable and consistent), then go for it and keep us very well informed as to your progress! Good luck! Regards, Scott F>

The Sandbed-Shaken- Not Stirred? I've created a DSB in my marine tank. <Good for you! An excellent technique to reduce or eliminate nitrate continuously and naturally!> I wonder if I should add any sand shifting (if so which ones? I need some reef safe ones) organisms. <Personally, I am against the heavy "stirring" of sand, by both the aquarist and sand-dwelling animals. I like to disturb the sand as little as possible. IMO, It's okay to stir the very top layers (no deeper than 1/2"-3/4" or so, just to keep the sand from clumping, but it may not really be necessary if the system is well-maintained. If you are inclined to use "sand-sifting" creatures, I'd limit your "crew" to a few brittle stars. They do a great job at scavenging uneaten food and detritus, and do not overly disturb beneficial processes occurring in the sand bed.> But then, if they shift sand will that not provide oxygen to the lower layers of sand, so no anaerobic bacteria will grow and therefore no nitrate reduction will occur? Thank you. <Well, the argument for as little disturbance to the sand bed as possible holds well here! Over-zealous "maintenance" practices can interrupt the very processes that you are trying so hard to foster! Read a lot more on sand beds in Anthony and Bob's new "Reef Invertebrates" book! God luck and enjoy your system! Regards, Scott F>>

Point-Counterpoint... Thanks for your time on this. <Our pleasure- we love this stuff! Scott F. here today> I have been doing a lot of research on marine aquariums (books and internet searches) and what I am finding is that there are a number of diametrically opposed views about the aquarium. <Different views? On marine aquarium keeping? Really? LOL> I have read enough articles on WetWebMedia to know what you believe and I would like your opinions on some of these differing thoughts. <Sure- I'd be happy to!> 1) It is a universally accepted principle that aggressive protein skimming is a must (1 cup a day) for nutrient and allelopathy export.  In addition, to successfully grow corals, micro-organisms such as zooplankton, phytoplankton, etc., (whether grown in a refugium, a reactor and/or green water additives) is also a must.  However, protein skimming removes these micro-organisms from the system and there some thought that protein skimming is as harmful as helpful.  The no-protein skimmer belief rests upon refugium/Caulerpa/seagrass and/or clams as a more natural mechanism.  Plus, there are less impellors killing the organisms (including powerheads). <Well, I am of the opinion that a well-tuned protein skimmer is absolutely essential for long term success in closed marine systems. I have heard from a number of people who yanked their skimmers-some have been successful for a while- many have gone back to skimmers. I like to think of the long-term with reef tank maintenance. Skimmers remove many noxious compounds and dissolved organics before they have a chance to degrade water quality. I have yet to see a very successful reef system that has been maintained for years without skimming. I do not consider  one or two years a success...The bottom line on skimmer use, in my opinion, is that if you are going to omit skimming, then you need to compensate somewhere- either with a much lower bioload, very aggressive water change schedule, alternative "filtration" techniques (like Steve Tyree's Sponge/Sea Squirt Cryptic Zone concept, etc.). It is a trade off, and one that I do not feel is worth it. As far as the impellers in pumps destroying valuable plankton is concerned- I have heard a lot of thoughts on this, and, quite frankly, I feel that the threat-although legitimate, is highly overstated. Most reef systems simply don't grow and support large enough populations of plankton for this to be a legitimate concern, IMO. Even with productive refugia and other supplemental systems, I just don't think that the impact is there> 2) To remove allelopathic compounds from the system, weekly carbon changes are suggested.  However carbon also leaches vital trace elements out of the system.  Once again, harmful and helpful. <I am a firm believer in the continuous use of small amounts (like 2-4 ounces per 100 gallons of tank capacity) of high quality activated carbon. Good grades of carbon, such as those offered by Seachem (my personal favorite), Two Little Fishies, or ESV do not leach phosphates into the system. Yes, carbon can remove small quantities of trace elements from the system. However, if you are following one of my other favorite practices in marine husbandry, frequent small water changes- you will be replacing trace elements on a regular basis. In fact, you will probably not experience a deficiency in trace elements if you practice these water changes> 3) Another universally accepted principle is weekly water changes.  When you have a 55 gallon tank, a 10% water swap is no big deal.  When you have a 125 with a 30 gallon refugium and 10 gallon sump, it is a much greater effort, requiring a large garbage can sitting in the living room overnight to allow the salt to fully aerate and mix before doing the swap.  Plus the swap tends to be somewhat stressful on the fish.  I am planning on buying a 300 gallon at the end of the year and turning the 125 into a large DSB/Live Rock sump. A 10% water swap on 425 gallons will be a huge effort! <As a fanatic about regular small water changes, I can tell you that the process is simply not that difficult. One of my systems has about 200 gallons total capacity. I change 5% of the water twice a week. This amounts to 2 10 gallon water changes, which I perform on Wednesday morning before work, and on Sunday mornings (unless the surf is good- in which case it's usually Sunday afternoon!). I will generally mix up the saltwater in a Rubbermaid container about 24-48 hours before, and then perform the change. I also perform minor maintenance tasks, such as a little extra algae scraping (if needed), coral pruning, etc. on Wednesday. This will take about 20-30 minutes to perform. On Sunday, I take a little more leisurely pace, and will clean the skimmer, replace carbon or Polyfilters if needed, change micron socks, or any other little things that have to be done. Maybe it takes about 45 minutes to an hour of pleasant labor. I have always done the additions of new water "manually", by pouring it into the tank from a pitcher. If I really wanted to do it quicker, I'd hook up a Maxijet 1200 powerhead to some 5/8 ID tubing, and "pump in" the replacement saltwater...it's a lot quicker. Frequent small water changes need not be a chore. Rather, look at them as an opportunity to regularly assess the situation in your tank. Anyone who maintains their own garden can relate to the labor involved. It is part of the "price of admission", IMO, and is simply not that difficult. And, when you see the difference in your animals, you'll realize that it's all worth it!> Lastly, I have and read about many a aquarist who has been very successful for years with minimal swaps, minimal effort by maintaining proper trace elements/calcium/alkalinity. <I have to quote Anthony on this: "Even a blind squirrel finds a nut sometimes!". It's just not something that you'd want to do. We are talking about living creatures here- which require us to provide the highest level of care. Closed systems are just that- closed, and unlike the ocean, do not afford the animals a constant influx of clean water. To those hobbyists who think that water changes are not required, I respond, "You wouldn't let your dog live in the same room for 5 years without cleaning out the waste, would you? Don't do it with your fish!"> 4) Bio-wheels and Bio-balls are sold in virtually all LFS and internet dealers.  They add a tremendous amount of stability to the system but also contribute nitrates because there is no anaerobic area for denitrification. Once again, stability vs. water quality, harmful and helpful. <These media are, in essence- "victims of their own success": They are so good at removing nitrites and ammonia, that they cannot provide a bacterial population to keep up with accumulating nitrate. Yep- it is a tradeoff. Frankly- I like to keep things simple, and use a more natural approach: Let the live rock and sand do your filtering, along with use of macroalgae in refugia, and protein skimming, water changes, and regular use of carbon and/or PolyFilter media.> 5) Allelopathy is another subject, not discussed at LFS trying to make a sale.  Some people claim that pictures of beautiful coral displays that are all over the internet will be very different a year from now because of allelopathy and others claim success for years in spite of pictures showing many corals side by side, touching each other.  Another subject in dispute. I have purchased very aggressive corals (not knowing better at the time).  I have multiple leathers, Ricordea mushrooms, 5" genitor, frogspawn, colt and bubble corals.  Is this a toxic soup, a ticking time bomb, or as others claim, no big deal. <Well, I would not call it a ticking time bomb, but it is not an ideal situation. This is an aggregation of animals that are rarely, if ever found in close proximity to each other on natural reefs, so there will be a certain amount of allelopathy. However, these animals can be maintained together in a certain "stand off" with use of aggressive nutrient export mechanisms (the aforementioned skimming, water changes, and use of chemical filtration media). It's much more ideal to develop a stocking plan that utilizes animals that live together in nature. However, as we often state, this is a closed system that we're talking about. It can be done-and done with some possible success, but it is not ideal. I have seen many successful "garden" reef systems over the years, so I can't say that it's not possible to do this. just not recommended!> As I plan for a big expansion of my system, these are the thoughts that come to mind.  Natural (refugium/Caulerpa/seagrass and/or clams) vs. mechanical (protein skimming).  I currently have both.  Is chemical filtration needed? <I believe that a "natural" approach, with a few technical props (skimming and chemical media) is the best approach for most systems> Are water swaps absolutely mandatory, which would dampen my enthusiasm for a larger tank.  Would removing some of the aggressive corals reduce the allelopathy problems or would the bigger tank mitigate them? <Yes, removing some of the aggressive corals could help, as would reducing the proximity between corals. However, it is still important to change water. I would have to say that it's mandatory! Please understand that it just is not that daunting a task...Small amounts often is not that difficult!> Long email.  Apologies.  Thanks for the time. <My pleasure! These were some excellent, thought-provoking questions that have stimulated many a late-night fish nerd conversation at a MACNA conference! I hope that you will be in this year's MACNA in Louisville so that we can discuss these things in more detail! Good luck! Regards, Scott F>

Ammonia in Change Water 07/27/03 <Hi there, PF with you today> Hey there Crew, I'm having a problem with Ammonia in my Change water.  I looked for about two hours searching for "ammonia in make up water", "ammonia in change water", and "ammonia in stored water".  I know I've read FAQs re: this same thing, but couldn't find it.  Here's the problem: I have a 2" yellow tang and a 2.5" Sebae clown in a 20 gallon QT, this after a rather nasty outbreak of Ich in the main system. They've been in there for the past two and a half months, while I redo the main tank.  They've been clean of any Ich since then, BTW.  I decided to add a Neon Goby (Gobiosoma oceanops ), for some help just in case.  Well, when he entered the tank he automatically hid.  No big surprise there!  A couple of hours later, he came out and was swimming in a jerking manner, and periodically acting like he had a hard time swimming upright.  He would sort of swim upside down or on his side, although he would right himself and perch on the side of the glass.  I didn't QT him, partly because I read from one of Bob's responses that they are generally clean and should be OK to go right in.  Also, the LFS I bought him from does QT all new arrivals for several weeks, and I didn't see any signs of Ich/velvet on any of their fish.  Maybe I made a mistake, I don't know.  Anyway, his swimming prompted me to test the water in the QT.  I've been doing 25 -50 percent water changes twice a week since the fishes have been there.  My ammonia showed at about .5 mg/L.  BTW, I used three different test kits, and all showed the same. I decided to test the change water and it showed .25 mg/L.  I use RO water from a nearby water store.  I usually make up about 20 gallons at a time in a Rubbermaid 31 gallon storage container.  I have a Rio 90 power head with air pump attached and a 150 Watt heater in the container.  I add the water, turn the powerhead and heater on.  After 24 hours, I add the buffer.  Wait another 24 hours, then add salt.  It then usually mixes for at least 36 hours, the whole time being aerated.  The water sometimes lasts me 2 weeks, but usually only one.  Am I doing something wrong?  I don't add any dechloraminator, as I've read on your site that it should be superfluous with the storing/aerating.  I've never tested the water from the store, but I will be asking them for their test results.  Any suggestions would be great. <Well, the store would be the first place I check. They could be using old membranes on their equipment. Your makeup routine sounds good. Personally, I use dechlorinator (use one that smells like vinyl), and then buffer the water back up to the appropriate pH. You might want to invest in your own RO/DI unit. Hope that helps, PF>

Twice Weekly Water Changes...! Dear Scott F. <Hi there!> If your the ear today, I have NO questions.  This is a pat on the back.  Your 5% water change article is pure genius.  In one week, ONE WEEK... I noticed water becoming crystal clear, corals "perking" and one happy blue Pacific tang. <Cool!> My 100G reef is reborn and the water change is a snap.  Thank you, Thank you, Thank you. <You're VERY welcome! It's great to hear that this technique is working for you! It only sounds tough, but it really does work! I'll bet that our fellow hobbyists would have a lot fewer algae problems, elevated nitrate levels, and enjoy just better overall conditions for their animals. Keep spreading the word on this technique! It's funny, all of my skeptical friends who embraced this technique have been thrilled with the results, too. Could it be that water changes are a good thing? YEP!> By the way. read the Deep Sand Bed article and tried it with 4 inches of aragonite... SWEET!!  All of you deserve recognition. Sincerely, Steve Collyer Modesto, California <Thanks so much for the kind words, Steve! We have some very special people on this Crew who really love sharing with our fellow hobbyists! Be sure to keep sharing your experiences with others, so that we can all benefit and learn together! Regards, Scott F>

Salty Skimmate? Dear WetWebMedia, <Hey! Ryan with you> I am aware that we must replace water in our marine aquariums that is lost do to evaporation with an equal amount of clean fresh water. <Yes> However, what do we use to replace the water lost by skimming? <Nothing.  Taking a measurement of your salinity and making an adjustment with your weekly water change is adequate.>  I guess my real question is, is skimmate salty or not? <Sure> I'm not about to taste the skimmate to find out! <Aw, come on.  All the cool kids are doing it!>  Also, I am trying to find the proper setting for my skimmer.  I believe that getting it to produce the thicker gross looking foam as opposed to just slightly cloudy water is best.  However, when set up like this there is numerous times during the day where no skimmate is produced. <With a well established tank, there can be periods in the day where the skimmer doesn't produce.  This is pretty uncommon, and usually only in lightly stocked tanks with lots of live rock.  Check out Reefcentral.com for ideas on how to fine tune your skimmer- modifications may even be available.>   I assume that is normal and I should stop futzing with the skimmer settings and just let it do it job?  <Not if it's not doing it's job!  You should be able to see a difference in your water testing if your skimmer isn't cutting it.  If you've kept a log of water quality this will be easy to see.  Good luck, Ryan> Thanks for providing such a great and informative site.

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