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FAQs on Marine Water Quality involving Phosphates, Troubleshooting/Fixing

Related Articles: Phosphates in Marine Aquarium Systems by Marco Lichtenberger, Phosphates in Carbon; An analysis of the phosphate content of activated Carbon by Steven Pro, Ammonia, Nitrates, Nitrites, SilicatesMarine Chemical Filtrants,

Related FAQs: Phosphates 1, Phosphates 2, & FAQs on Phosphate: Importance, Science, Measure, Sources, Control, Chemical Filtrants, & Nitrates, NitritesAmmonia, Silicates, Avoiding Algae Problems in Marine System, Nutrient Control and Export, Algae Control, Marine Maintenance, AlkalinityChemical Filtrants

Where, when in doubt, water changes are always a good idea.

High phosphates have me puzzled  2/4/11
Hey Crew! Thanks for your input on a different topic, right as usual.
One month ago I acquired a used reef setup, with only a few live coral (mushrooms and polyps). After moving the tank and successfully keeping things alive, I tested phosphates at ~10ppm and nitrates at >80ppm.
A couple of
rapid water changes ensued. Here are my current tank specs.
90 gal w/25 gal sump
5 gal refugium w/DSB, Chaeto, mangroves
150lbs LR
No substrate
6 bulb T5s (new)
reef octopus skimmer (new)
39 watt UV
1 ocellaris clown
1 firefish
3 chromis
1 hippo blue tang
1 yellow tang
0 ammonia, 0 nitrite, <5 nitrate (and falling), 8.2 ph, 8 dkH, 420 calcium, 1.0 phosphate.
<Still high>
After several water changes, using/replacing 250 ml of Phosguard per week, and dosing daily with Ultralife reef liquid phosphate remover, I've been able to bring the phosphates down to 1.0ppm. However, its been hovering between 1.0-2.0 for the last 1 1/2 weeks with no signs of dropping.
Cyano has been a real issue for the last 2 1/2 weeks (obviously). I'm performing twice a week 10% water changes with RODI water (tested clean), was feeding twice daily (2 small pinches in the am, 1/3 cube frozen in the pm (thawed to remove the packing water)), but have now reduced that to once daily.
I'm at a loss on what else to do to bring the phosphate down. I'm suspecting the LR is leaching phosphate,
<Time to test for such... take a piece out... soak it in just new seawater of known HPO4 conc.>
perhaps due to poor husbandry from the previous owner? But in the month I observed the system in his care, he never had any algae/Cyano outbreaks. Any suggestions?
<Do read here: http://wetwebmedia.com/phosphatemar.htm and the linked files above>
I'm also having trouble getting the Chaeto to grow. Fuge turnover rate is at 15-20x,
<May be too high>
and I have over 25 watts of CFL daylight 6500k lighting. I've tried alternate light cycles with the main tank and also constant 24 hour. The constant lighting seemed to work best, but even then I didn't see the fast
growth I'd expect with such high nutrients.
<Something else (necessary) is likely rate limited, and/or it's being poisoned by the BGA>
Thanks in advance for any help. WWM truly is a wealth of info!
<Keep reading for now. Bob Fenner>

Unstoppable phosphates 12/1/10
Hi crew,
I tried my best to figure this issue out on my own but it seems I need your help here.
I have a 90 gallon marine tank with a 4.5 - 5 inch deep sand bed.
My tank has been running for almost a year and the parameters are as follows:
Ph - 8.3
Ammonia - undetectable
Nitrate - undetectable
Nitrite - undetectable
Phosphate - 2ppm!!
Ka - 9
Ca - 400
Sg - 1.025
Let me fill you in on some history regarding this tank. Nearly a year ago I began running this salt tank with two clownfish, three damsels, and a green chromis. At that time my sand bed was about three inches
deep, I had and still have around 100 pounds of live rock,
<Could be a source>
and the only mechanical filtration system was my Fluval 405 canister filter.
I was not using a protein skimmer.
As the months passed I tried my hand at one or two more small fish (2 - 3 inches max length) and added ten Nassarius snails and a golden head sleeper goby to help clean the substrate. It seemed the "cleaner
crew" was doing a fair job at cleaning the sand bed (almost sugar fine).
<Aragonite I take it>
After about seven months I added another 1.5 inches of sand to my substrate resulting in a 4.5 - 5 inch DSB which at this current moment is rich in fauna and seems to have banished any detectable nitrate in the water column because I cannot get a reading from my nitrate test kit (API test).
<Not the greatest kit; but could be all gone, ongoing>
I will acknowledge my faults as a beginner in this hobby and can honestly say that for 3 or 4 of the "in between" months I overfed the tank. I justified this by wanting to make sure the snails and goby got enough to eat. At the same time I was not performing adequate water changes (10 - 15 gallons every two to three weeks) and had not yet employed the services of a protein skimmer. I was using well water to mix my salt and was not testing the supply water. Needles to say these were great examples of poor husbandry.
About a month and a half ago my tank experienced a bad Oodinium outbreak (no quarantine tank) and all of my fish perished. At that point I swore a personal oath that I would do absolutely everything in my power to ensure the water quality in my tank be nothing less than top notch before introducing any other fish. A week later I had a Remora Pro skimmer scrubbing my water of any DOC's it could manage to
skim. I started doing water changes with RO/DI water (0 TDC before mixing, tested with a TDC meter) and are performed on a weekly basis (10 gallons per). I have converted the Fluval 405 canister filter to
a sort of Phosban/carbon reactor. I have also set up a quarantine tank for any potential newcomers.
<All sounds/reads good>
Because I am letting the tank run fallow save for two shrimp and some inverts (snails and such) I have not been feeding the tank other than a minute amount of small fragments of thawed prawn for the two cleaner
shrimp. I have noticed that all traces of ammonia, nitrate, and nitrite are undetectable by my test kit but the phosphates are non stop at 2ppm. I have tested my supply water (well water) and found that about .5ppm is detectable (I tested this because I had been using straight well water mixed with instant ocean prior to buying the RO/DI machine). The water coming from the RO/DI reads 0 across the chart. I estimate that I have since replaced around 30-40 gallons with RO/DI water through water changes and top off.
<Okay... should keep diluting with further change-outs>
The question that this lengthy email has led up to is this: is it likely that the phosphates detected in my tank are a result of some buried nutrients in the sand bed
<Mmm, not buried, and not from a commercially-available aquarium substrate>
and if so, how can I safely remove them without destroying the basic function of the DSB itself or polluting the tank with potential noxious gas from the deeper regions of the sand bed?
<Well, first off, I'd "test the tester"... Check out your test kit, some samples of water against another (better) kit/assay). Next, I'd read here:
and here: http://wetwebmedia.com/phosphatemar.htm
and the linked files above carefully. Next, I'd not worry re soluble HPO4 and keep running the system as you are currently... Lastly IF I had appreciable "trouble" linked with the phosphate (excessive pest algae for instance), I'd look for, apply means to diminish it here>
I did run some simple tests to find out if there were any portions of the sand bed that might be going bad. I siphoned some water from the bottom of the left, middle, and right sections of the sand bed. I found that in the center of the bed the ammonia was 0-.25ppm, nitrate was 80-160ppm, and Phos was 2-5ppm.
<Not surprising eh?>
In the left portion of the bed the readings were the same except nitrate was 20ppm. In the right portion ammonia was 0ppm, nitrate 20ppm and Phos was 2ppm. At no time did I ever see any black or discolored water or black or discolored sand and never noticed any kind of foul odor.
Does this sound normal of a functioning deep sand bed,
should there be high readings like this or is my sand bed failing, if so, what can I do to remedy it? If it is already doomed, can I just remove the live rock and inverts and stir the sand around and let my canister filter suck out any organics?
<Not likely to improve the situation. The present DSB is better, fine>
Should I wash the sand (killing any beneficial bacteria in the process) and then start over.
<I would not>
Would the addition of extra Nassarius snails help in a "search and destroy" type of solution?
I would like to try my hand at this hobby again but like I said earlier, I will not add anymore fish until my water is perfect. Sorry for the long email and thank you in advance for your attention to my problems.
Humbly Yours,
<Mostly I wouldn't worry Sean... the phosphate will diminish with your (now) good aquarium maintenance practices with time. Bob Fenner>

Serious Phosphate Problems? 9/4/10
<Hi Dirk>
Are my rocks wasted or is there anything else I can do?
<Don't know, have they been drinking? :-)>
Had a serious Phosphate problem in my tank with my levels going not mesmeasurableowing <below> 20+ on the API test kits. Tried another test kit and same result.
<Same brand, API?>
Anyway I decided to take drastic messumeasures <measure and> broke down the  entire
tank due to many other issues. Anyway I gave the rocks a Muriatic bath (2 sessions of 30 minutes in a 10/1 mixture) which made the rocks come out real white and clean. Had them rinsed for a week in regular water changing the water every day even the first 2 days twice a day.
Put the rocks in a closed container with saltwater (Boiling) now for almost 1,5 weeks. First 3 days changing the water daily 100%.
Since then (7 days) had the same the water sit with several powerheads inside the bin.
Now after those 7 days wanted to do again a 100% water change but before checked the water and tests showing again 5.0 phosphates????
Now what to do???
Are my rocks lost or should I keep doing daily water changes but for how long?? Or is there anything else I can add to have another Phosphate treatment done?
maybe get rid of the rocks?
<My only thought here is that phosphate is being introduced by another source. Have you ever did a phosphate test on your source water?>
Thank you
<You're welcome. James (Salty Dog)>
Re Serious Phosphate Problems? 9/4/10 - 9/5/10
<<Hi Dirk>>
Are my rocks wasted or is there anything else I can do?
<<Don't know, have they been drinking? :-)>>
Had a serious Phosphate problem in my tank with my levels going not mesmeasurableowing <below> <I meant showing> 20+ on the API test kits. Tried another test kit
and same result.
<<Same brand, API?>> <Salifert>
Anyway I decided to take drastic messumeasures <<measure and>> broke down the  entire tank due to many other issues. Anyway I gave the rocks a Muriatic bath (2 sessions of 30 minutes in a 10/1 mixture) which made the rocks come out real white and clean. Had them rinsed for a week in regular water changing the water every day even the first 2 days twice a day.
Put the rocks in a closed container with saltwater (Boiling) <I believe the right term is cooking?> now for
almost 1,5 weeks. First 3 days changing the water daily 100%.
Since then (7 days) had the same the water sit with several powerheads inside the bin.
Now after those 7 days wanted to do again a 100% water change but before checked the water and tests showing again 5.0 phosphates????
Now what to do???
Are my rocks lost or should I keep doing daily water changes but for how long?? Or is there anything else I can add to have another Phosphate treatment done?
maybe get rid of the rocks?
<<My only thought here is that phosphate is being introduced by another source. Have you ever did a phosphate test on your source water?>>
<Yes I did test the source water as I am using treated ocean water with no trace of any phosphates in it>
Thank you
<<You're welcome. James (Salty Dog)>>
<Back to original question. Is there anything else I can do as I really
<<really>> don't want to re-introduce any phosphates back into the new set up tank>
<<I would suggest using a good salt mix rather than ocean water. Natural seawater contains orthophosphates (HPO4) and at higher pH, the equilibrium shifts toward more PO4 (phosphate) and less HPO4.
I do not know if this is what is happening in your system, but it's worth a try using a salt mix rather than ocean water and note any changes. Bob may input here as well. There are means of controlling phosphate as in protein skimming and the use of RowaPhos in a reactor. All foods contain phosphate to some degree and is a possibility that the food you are feeding is high in PO4. I suggest
reading here and related articles/FAQ's for additional help. http://www.wetwebmedia.com/phosphatemar.htm
In future replies, please do not insert carets within the text, makes it difficult to sort out who wrote what. Replying to the original thread makes it much easier for us. James (Salty Dog)>>

High Phosphates 3-31-09
Hello Crew!
<Evening, Mike here>
I have been having a very difficult time reducing phosphates in my 260 Gallon Reef Tank.
Specs are:
260 Gallon + 60 Gallon Fuge, 4x250 MH - On for about 8 Hours daily, 2x72" actinics, Moon Lights, Chiller, ASM G3, Skimmer that is filled up almost daily.
Use RO water for top off.
Shallow Sand Bed
Running Bioballs carbon in sump
<An odd and difficult way to run carbon>
Running Seachem Denitrate in reactor
Running Phosban mixed with RowaPhos in reactor
Dose Calcium, buffer, 8.4, Fuel, iodine, strontium. about once a week each.
Calcium and buffer on diff days then strontium.
<Nice system>
Chemistry is within normal param.s except for the PO4 at .5, nitrates sometimes up to 15 but usually below 10... SG is at 1.023 but bringing up gradually to 1.026 as suggested by others.  I have a very large lump of Chaeto algae in the sump w/ live mud, live rock, and keep 6500k lamp on 24.7 to encourage the algae to do its job.  (Should I take out the algae in some fresh salt water to shake it out on occasion as it gathers much debris being in the flow)?
<Couldn't hurt...>
Feedings consist of:
1 Tbs of spectrum pellets in the AM.  At night they get some combo of Nutramar ova, seaweed (1/4 sheet), mysis, Spirulina, or krill) - Never all at once. probably amounts to about 1.5 -2 tbs daily. It seems like a lot but my fish eat it all within a few minutes and seem to beg every time anybody approaches the tank.
Coral 1-2 times per week a mix of DT's Phyto, DT's oysters, Kent sea Phyto, Chromaplex, Cyclops-eeze, Kent Zooplex, coral frenzy. (I would say all amounts to about 4-6 TBS 2x weekly).
I have 4 anemones and 4 plate corals that get about 3 shrimp divided amongst them 1x weekly (the Duncans usually get some of that too since they eat it)
<Not the best system for anemones, but so be it>
I have about 40-50 pc.s of LPS/Soft Coral.
<a PO4 reading of .5ppm isn't going to detrimentally affect these coral species to a significant extent>
I have about 20 Fish... 5 tangs 3-6" and the rest are little fish like Anthias, clowns, blennies, etc..
<Pushing the stock limits...>
Also have many snails, and made the mistake of getting hermits, 2 sand sifting starfish that have manage to stay alive for about 6 months now, one urchin, and about 100 super Tongan Nassarius snails to keep the sand bed clean - maybe less since the hermits very much enjoy taking their shiny shells.
<I'm not a fan of hermits either>
I perform RO water changes of about 40 gallons weekly since this has happened. Before it was 40G twice monthly. Do I need to do more than this?  Its a ton of work to get done every weekend with no effect!
<Shouldn't be that difficult...40 gallons is ~1/6th the tank volume, I'd do at least 40 weekly or 80 bi-weekly>
I am curious what exactly the issue may be? I have reduced feedings to half with no effect - water changes don't see to make a difference at all. All of my liverock was deepwater from Vanuatu (sp?). It was completely algae free after curing and the tank tested undetectable for PO4 before we went ahead and stocked anything. So I am pretty sure its not the rock or sand in there. My only suspicion would be the carbon or feedings but it really makes no difference if I change/remove.
Do you have any suggestions on improving the water quality or what may be causing this.
<If you've made drastic changes and are consistently getting a phosphate reading of .5ppm, it might be time for a new/different test kit>
Also on a side note.. my snails decided to eat a clam and I didn't notice until we had a Cyano outbreak.. is that typical? I didn't think snails would go for a clam?
<The clam died, THEN the snails ate it, not before, unless you are referring to parasitic pyramid snails>
Thank You,
<Anytime - but next time, please run a spell check on your email so I don't have to proofread it>
<Mike Maddox>

Re: High Phosphates 4/25/09
Mike - Thank you so much for taking time to answer my email.
<Hello Cassidy, Scott V. with you, sorry for the slow follow up here.>
I have been able to get all my levels down to what I think is good but the issues of BGA still persist.
<Even with all well it will take some time to battle.>
I am not sure if it should die off or what now? I have removed as much as possible manually from the tank but since there is about 500 Lbs of live rock in there it's a rather difficult task.
<Wow, I bet!>
I am still noticing that some coral tissue is receding slowing and being over taken by the algae. Is it best to cut away the dead skeleton of the coral and dip it?
<I would not, better to change things in the corals' favor...and away from the BGA.>
My phosphates test .1 with Salifert test, red sea test, and API test kits.  So I know that isn't the issue now.
<It could be if the BGA is consuming the PO4, making the reading artificially low.>
So basically I am wondering if the algae will continue to thrive even though there are no phosphates in the water, or will it die off and release all the PO4 back into the tank?
<Possibly one, then the other. You will have water changes in your future.>
I am wondering If I need to take out all the LR and clean by hand or let the clean up crew do it?
<A clean up crew will do no real good with BGA. Keep your system stable and with good water quality to kill off the BGA. This will happen slower than most of us wish!  As the stuff dies you will need water changes to keep the water quality high...keep siphoning out what you can with the water changes.>
All other readings seem good aside from Nitrates which are between 10-15 constantly.
<Should be lowered in time with proper care.>
I have been thinking about getting a Korallin Sulfur based De-Nitrator - But am concerned about low PH in the system. I will be adding a MTC Pro-Cal Dual Chamber Calcium Reactor this week. Do you think the two would be in constant odds with each other?
<Not with each other, but the accumulative effect of CO2 may need to be dealt with, aerated before the water is returned to the tank.>
My other concern is the sulfur media, I read on your site that natural sea water contains about 2600ppm sulfur. Seeing as there isn't any easy way to test for the sulfur content in my tank should I be concerned with that?
<Nope, not an issue.>
I also had an completely unrelated question - A friend of mine has a rust issue happening in his tank and I couldn't find anything about it on your site. Would the rust or iron oxide be of any concern in a reef tank?
<Not unless it is acute, an extreme case.>
He has since corrected the issue but is afraid it may be too late since his tank has been exposed.
<Any affects would be seen quickly, it is basically a poisoning incident.>
Thanks for your time - Love the site.
<Welcome, Scott V.>

Toxicity in sps reef 07/16/08 Hey guys, just had a quick question regarding a vexing issue I have been having. Long story short, the phosphate remover I was using <Mmmm, am compelled (by myself natch) to make a comment that by and large I'm not a fan of hobbyist use of such... unnecessary, better means...> caused an issue with the water's supersaturation point (despite mg of 1400 and frequent water changes, the max at which I could keep alk and ca kept dropping to the point where I could only get alk of 7 and ca of 360. I did extensive reading, and through much trial and error, finally determined it must be GFO (other reefers have reported the same) <Mmm, for browsers... iron oxide hydroxide: A nice piece here re: http://reefkeeping.com/issues/2004-11/rhf/index.php> , I removed it, did a few large water changes and my sps started coloring in colonies I hadn't seen color in over a year! <Ah, yes... some HPO4 is absolutely essential to all life we're interested in> My issue is that the low alk levels brought on the onslaught of Cyano, I run a very clean system, let frozen foods thaw first before use, have a killer skimmer, no sand beds, very little detritus, heavy oxygenation, run ozone, change carbon weekly, use Purigen. My ph is 8.4, alk 12, ca 400, salinity 1.026, no ammonia, trites, or trates but I cant seem to kick the Cyano. It built up over a week so I put a filter sock on the output of that tank and cleaned the tank up. <Good> Within the next few days, sps that had been coloring started losing color again, but have good polyp extension. Some zoas are not opening up either. I have read posts by people saying that when they removed Cyano it caused problems for them even killed fish! <Mmm... one must proceed... cautiously here... BGAs can cause havoc... coming and going> Is it possible the removal of Cyano is stressing out the sps, <Yes> or is it more likely they are just stressed from the changes in alk, ca, mg. <Could be both, either> I have made changes slowly, and use baked baking soda (that's why ph is 8.4). <Mmm, not by itself... sodium bicarbonate> My alk has been over 10 for a week and yet I am not seeing coralline growth. Outside of a few water changes, do you have any recommendations? <Mmmm, "punt"... keep changing water, stop using iron hydroxide... All else reads as fine, should be fine in time. Bob Fenner> Rock Leaching Phosphate, Is It Harmful To Fish?...And...After 8-Weeks Fallow, Will My Ich Return? 01/12/08 Hey Eric! <<Hey Don!>> Hope all is well with you. <<Not so bad Currently devoting most all my free-time to a very large renovation/remodeling projectcant say I wont be happy when its done>> I have a question about live rock and phosphates. <<Okay>> I bought some base rock cheap, covered in coralline algae, and I know it's been in the tank for over a month being kept with fish and other animals but they told me that I wouldn't want it cause it leeches phosphates. <<And yet you bought it anyway [grin]>> They told me it was cured so I took it and put it in quarantine and I haven't gotten any readings of phosphates. <<Very good>> Would the rock after being cured be o.k. to put in the main tank or does certain rock always leech phosphate? <<Most any rock can be a source of soluble Phosphatebut your tests seem to bear out that this rock will be fine>> Also do phosphates kill fish? <<Hmm, I suppose theres a limit where it could. But in my experience with systems with very high Phosphate levels the fish did not deem bothered directly>> I never had a problem with it and tried to read as much as possible but there were no FAQs that I could find about it. <<Mmma quick search turns up nothing specific to this for me either. If I am off track/if more need be stated, I trust Bob will interject>> I finally put the fish back in the 210 after 8 week quarantine. <<In regards to your Ich issue, yesexcellent>> What are the chances of the main tank and fish being 100% cured because after this live rock is done I was thinking of Hippo Tang to put in the quarantine but if it's not likely 100% then I'll probably not bother with tangs. <<The eight-week quarantine/fallow period will go far towards achieving an Ich-free environmentfor a time. But as I think I have mentioned before This protozoan pest is so easily introduced, even from non-organic and non-fish sources (e.g.- live rock, inverts/coralseven from using a net from another tank) that it is not realistic to expect to never see it crop up again. Thus the importance to continue with proper quarantine, proper stocking levels/environmental conditions, biological controls (e.g. - cleaner shrimp/gobies), et al. With these considerations, I see no reason to stay away from tangsthough I might consider a different specimen from the large and very twitchy/nervous species you have selectedperhaps Acanthurus japonicusor one of the commonly available Ctenochaetus species>> I really don't want to break down a 210 tank again! <<Ill bet!>> Thanks again. <<Always welcome>> Any chance of you going to MACNA? <<Indeedhave already made reservations and payment to attend>> I was thinking of going to Atlanta in September to go. <<Perhaps I will see you there>> Talk to you soon. Don V. <<Cheers mate. EricR>>

Tap Water and Phosphate  - 02/22/07 Hopefully a quick question.  Can I still have 'problematic' tap water if I am showing an untraceable amount of phosphate in my tap water?   <Yep.> My reef tank is still getting signs of Cyano on the sandbed after 5yrs.  I've tried Chaeto (which is still growing strong ~ despite my last email.... It's still healthy... I figured rotting Chaeto might be supporting the Cyano... but it was just dirty Chaeto that I rinsed in saltwater), water flow is 16x/hr, I underfeed my critters.  I have all kinds of good algae's growing.... But the sand consistently turns a goopy burgundy.   <Nasty!> It must be my water then? <Could be.> Yet I can't get any signs of phosphate from a Salifert test.   <Currently all being used to feed your beautiful Cyano!> I think the last resort is an RO unit? <Or a supply of DI/RO water.  LFS or some local supersaver centers, think Wally world here, sell RO water.  A pain to haul around large quantities of water, but could be a quick fix.  Experiment to see if a large water change with RO water shows any improvement.> On a different note...   ever been diving in Roatan?   <Nope, not yet.  Hopefully some time soon!> If so, how was your experience?  I'm hoping to be able to dive with some whale sharks, grey reefers, maybe even a bull or Mako. <I'm more into the small, colorful, fish myself.  But was quite awed hearing the song of the humpback whale while in Hawaii.  Seeing them breach in the distance was pretty sweet too!> Regards, Dave Brynlund <Cheers, -Mich>

Re: Tap Water and Phosphate   2/23/07 Thanks for the response Mich! <You're welcome Dave!> So basically, tryout some bought DI/RO water in a few water changes... And if it's working, then invest in a unit.   <Yep!> Never woulda thought to buy the water first.   <Sometimes it's the obvious that isn't so obvious.> Thanks! <Welcome!> Re: Diving... Yes, the small critters are certainly cool to look at... <And take pictures of!> But some of these big fish will certainly get the blood pumping. <Are we an Adrenaline junkie?> It's an interesting experience. <Mmm, interesting wasn't the first word that came to my mind!  Hehe!  Better you than me my friend!  -Mich> Dave Hi alk and hi calcium   3/4/06 A chemical mess Hi- <High> I have a 109 gallon reef tank with many mushrooms, SPS corrals, <Yee hah! Head 'em up little doggies!> two clowns, two wrasses, a large anemone and lots of reef janitors. <Union or no?> It is an established tank (over 2 years).  Everything is doing fine, but I notice limited growth in coralline and all corals. I had a smaller tank previously with no substrate and always had issues maintaining alk, ph and calcium levels but had extensive coralline and coral growth so I talked with many experienced aquarists and they recommended a plenum system for my new tank in order to help maintain ionic balance. <... Mmm, better to go with no substrate rather...> Since I had the plenum all tests have been relatively normal as you will see below except my alk is always hi at 18dkh plus and the calcium is always around 480-500.   <... define normal> I read all of your articles and summarized that not too many aquarists have this issue and have not had the "snowfall" issue that some others had.  Here are my readings. 18 dKH, calcium 500ppm, phosphates have always been hi-over 5mg/l, salinity at 1.021, <... should be near/er 1.025> Ph is 8.4 during day and 8.3 at night, ammonia and nitrite are zero, non chelated iron is zero, chelated is also around zero but I have been adding iron weekly so I am thinking my test kit is too old. Nitrate is around 40ppm <Way too high> and the r/o water is at 10ppm <Your unit needs maintenance, cartridge replacement> (but I use Seachem Prime to detoxify).  All of my other test kits are new (Salifert test kits for alk, ph and calcium) I noticed that since the alk and calcium were hi the amount of skimming debris has been reduced.   <Ahh! Yes> I use a Rena Filstar Xp3 canister filter, a sand bed filter hang on filter, 2x250 metal halide lights with two Marine-Glo actinics, an Aquarium systems hang on protein skimmer and two powerheads on a aquarium systems wave timer.  I use a five stage r/o system and the water alk level tested from it is 2.6dkh <What should this be?> with a ph of 7.0. I have little algae growth (coralline or green/red) and the only additives I have been using to try and increase coralline algae growth is Purple Up from CaribSea and Kent Marine Iron/Manganese. Other additives are Seachem Prime (only with water changes), Red sea Salt (again only with water changes) and Wardley's sodium biphosphate <... not a good idea... among other things, a source of your phosphate...> to lower ph/alk.  The hi calcium levels spike when I use Purple Up but otherwise maintain at 500ppm. I perform a 5 gallon water change every 3-4 weeks and change filter media every 2 months. With my old system (without plenum) I would have to change 20-25% water every week and dose heavily with calcium and buffers to keep my ph, alk and calcium normal.  I have been told by other aquarists to not change the water as frequently and this will lower my alk/calcium levels, but this is not the case-I actually find my ph and alk with rise while calcium stays the same. The only answers I can think of is either my liverock, base rock (I have over 200lbs) or the substrate of over 2" thick of crushed coral maybe producing the hi levels of alk and calcium and therefore may have to be reduced or start with more water changes and or adding Wardley's sodium biphosphate.  In the past I tried this but had only a temporary reduction in alk.  What about using acid or vinegar?  What are the dangers of this? Does coralline algae grow better in lower alkalinity tanks? I was hoping there would be a safe additive that I could use-can you help? thanks in advance, Al Standaert <Where to start here? You have a sort of "Dead Sea" effect going with the mix of chemical species present... If this were our only correspondence, I'd encourage you to re-read what books you have, worthwhile (accurate, significant, meaningful) parts of the Net... on marine water chemistry en toto... You can/could do a few things... but don't know you well enough to gauge whether you have the wherewithal to look into (sufficiently), stick with a given plan... I'll grant you a clue though: Simply adding more of anything won't help you here. What do you want to do... change out the substrate (entirely or almost), large consecutive water changes to get you (back) to somewhere you can grow corallines? Read and think this over... Bob Fenner> Protein Skimming Power/Phosphate/DSB removal  7/15/06 Hello, Thanks for running such a great site.  I've learned so much from reading your Q&A's. < Bob and the others do a wonderful job! > I have a 55g reef tank with about 50 lbs of live rock and a 4" deep sand bed.  It's about 15 months old and so far everything has been working very well, except for a recent, steep phosphate spike.  Is that typical for a DSB? < No, that is not typical at all. >   (I don't believe it is from overfeeding.) < Are you feeding frozen foods? If you are not rinsing the foods well, the phosphate from the juices could be encouraging the spike. Another thing to consider, if the prepared foods have fish meal in the first five ingredients, the phosphates could be coming from that! >   Is an extremely high level of phosphate a possible cause for my losing a number of fish recently, a day or two after acclimation (which I normally do gradually over about 1-1/2 hours)? (It's not due to a mantis shrimp;  there is no clicking, and no sightings at night.) < I seriously doubt the phosphates would cause that kind of reaction. I would look more at temperature fluctuations, or the possibility of airborne pollutants. > After talking to a couple of LFS, I'm becoming convinced that the DSB will eventually crash, and I am planning to remove it soon.  How gradually do I have to do that? < A four inch sand bed is not deep enough to really cause a serious problem, but if you must remove some, only remove an inch or so. Remember, the sand under the first inch layer is horribly toxic. Don't stir up too much! > My main question has to do with skimming.  I have an Aqua C Remora (not Pro) with the Maxijet 1200 powerhead and overflow box (I have no room for a sump).  One LFS is saying that that is not enough skimming capacity for a 55 g tank.  Currently I have four small fish, a cleanup crew of 20 hermit crabs and 15 snails, four small colonies of mushroom polyps and two small frogspawns, but I hope to add a few more fish and many more corals.  How much skimming power do I really need with this setup, once the DSB is gone? < That is directly related to the amount of food you feed, and the frequency of partial water changes. To place exacting limitations, or requirements on such is difficult. > < Yet another thing to consider is the possibility of your source water or supplements containing phosphates. Be careful when adding anything to buffer the pH, for nearly all related products use phosphate buffering agents! > Many thanks for all your help < I hope I was indeed helpful! > Bob < RichardB > "Sponges grow in the ocean. I wonder how much deeper the ocean would be if that didn't happen." ~Steven Wright Cyano problems and problematic stars 6/14/06 Dear Crew <Hi> I'm having a pretty big problem with Cyanobacteria.  My phosphates are high, so I'm currently using PhosGuard to try to bring it down.  <Check for the source as well, better to never have it in the tank than try to remove it later.>  Other than phosphates, ammonia and nitrites were 0, nitrates were 15, and ph was 8.0. <PH is a little low, but not to bad.>  A marine biologist at a local fish store said to put a dose of erythromycin in the tank to kill the Cyano and then to vacuum it out along with a water change.  She also told me to put snails and a sandsifter starfish in the tank to eat the organics and detritus in the substrate, and to help aerate it.  Unfortunately, I woke up the next day to find all of the snails and the starfish dead.  This brings me to my first question: Are there any flaws in my plan of attack against this Cyano?  <Oh yeah.  Erythromycin, along with killing the Cyano, will also kill most of your biological filtration, leading to a whole bunch of problems.>  I don't want to do anything harmful to my fish or not do enough so that it comes back.  <Will come back as long as it has a food source and PO4 as fertilizer.> I also want to know, what does a starfish look like when it is dead?  I heard they get soft and jelly-like.  <Sometimes> My starfish definitely is not soft.  It is quite hard actually.  I believe it is dead because it did not move once since I purchased it last night.  This morning, when I lifted it up to see if there was any movement from its structures underneath, I noticed a lime green/yellow on the sand where it was laying. <Not good.> The starfish did not bury itself at all or move to a new location.  Even though it is not soft, is my starfish dead? <Could be, if it has not moved at all and you see no tube feet moving, likely dead.> Thank you, Mike <Find the source of the phosphates and manually remove as much Cyano as you can.  With time/effort can be overcome.  Stay away from quick fixes like antibiotic, nothing good every happens fast in aquariums.  Also few creatures consume Cyano so don't overdo it snails and other cleaner.> <Chris>

Cyano and stars Part II   6/16/06 Chris, <Hi> How can I find the source of the phosphates? <PO4 test kits.> What are common sources? <Tap water, food.> I don't overfeed the fish.  <Frozen food often can pollute the tank quickly.  Also some pellets/flakes contain phosphate.>  Also, when I do find the source, how will I remove it. <Ro/Di unit for tap water.  Switching food and feeding in a different manner.> Thought I'd let you know.  The starfish is without a doubt dead.  Got home today and now its a pale white/yellow.  So much for him.  <Sorry to hear.> Thanks, Mike <Anytime> <Chris>

Re: Algae Control   6/1/06 Thanx for the info. One more question.  Could a phosphate problem be causing the Cyanobacteria outbreak?   <Yes> Does activated carbon work well with a reef tank? <Yes, as long as weekly water changes are carried out.  I'd use Chemi-Pure or a Poly-Filter before carbon, works much better in helping to remove excess nutrients.  James (Salty Dog)> Phosphates and the Algae War  12/8/06 Hello Crew, <Hi> Hope I'm not bothering you, but I've got some questions about my algae struggles. I think, but I'm not sure, I've tracked down my algae problem to phosphates in my source water, so I'm considering buying the Kent Maxxima Hi-S RO/DI unit. <Ok>  Before I spend more money that I don't have, I want to make sure that this is the best course of action and that I'm not missing something.  Hours of reading through posts has left my brain hurting!  <Ouch> Since the very first day I've been battling algae in my 55 gallon tank with no success.  I'll spend 3 hours cleaning the tank and doing a water change, but within a day, the algae is back. After 2 days, everything is completely covered again.  There is brown hair algae as well as sections of green, and sections of brown algae diatoms?) over the glass.  Tank is a FOWLR running for 3 years with 40lbs of LR, a Remora Skimmer, and a hang on refugium full of Caulerpa.   Ammonia 0, Nitrites 0, Nitrates < 10 ppm.   My phosphate test is hard to read, but it looks like phosphate reads around .6 ppm. <That probably a good part of your problem.> Testing the source water reveals the same level of phosphate, so I'm thinking that's the problem.  However, shouldn't the tank read higher levels than the source?  <Not necessarily, the algae takes up the phosphate, making it seem like there is less than there is.> Reading through other posts, it seems that most people having phosphate problems have levels significantly higher than mine. <Sometimes they show 0 too, depends on how quickly the algae is using it.>  I'm guessing/hoping that this is because my test only tests for the one type of phosphate.  <Possibly a factor.> My one doubt is that I also have a 10 gallon tank which has absolutely no algae, but is overrun with Aiptasia as well as what I think are some type calcareous tube worms.  The phosphate level in that tank reads slightly higher maybe .8ppm).  Ammonia, Nitrates, and Nitrites are the same as the main tank.  Does the Aiptasia out compete the algae?  <Possibly> Do you think the RO/DI unit would be the cure?  <Cure, no.  But very very helpful.>  I know I need one, but if it won't solve the problem, I can use the money on something that might have a better chance of working. Maybe I should ask Santa!  <Heehee> Thanks so much for your time. Jeff <Quality source water is one of the most important aspects of a successful tank.  I think a good RO/DI unit will be quite helpful, but it will take a while to see significant result.  Continued good husbandry will go a long way too.> <Chris> Phosphates Hi Bob, Glad you're around to help!!! I'm having a problem with my LFS. I bought a clown trigger from him and two days later he died.  <Mmm, what sort of symptoms? Did the fish eat... ever? What else do you have in your system that is doing well? Need more clues...> I went back for a refund and he tested my water. My ph is 8.0, ammonia 0.0, nitrites 0.o, nitrates 15. He also tested for phosphates and said I was at 10.  <Yeeikes, this is HIGH!> I thought phosphate problems were mostly related to algae, I don't have an algae problem.  <Unusual that you don't have a bunch of algae growing here... I would test your water elsewhere/wise> This tank also has a lion fish, snowflake eel, valentini puffer and a damsel. No problems with them. I also found out that my LFS keeps his ph at 8.8. <What? Really... strange... not easy to do, safely... and many downsides in event of other troubles...> I harden my fish for 2 hours, slowly mixing my tank water with the LFS water before I release. So needless to say, he refused the refund. Is the high phosphates the cause of death or possibly the big change in ph? Thanks again for your help........Paul <Maybe a bit of both... this whole situation doesn't add up though... Ten ppm of soluble phosphate is very unusual period... w/o enormous algal problems almost unbelievable... a store maintaining a pH (likely with Kalkwasser and careful use of calcium chloride) to maybe precipitate phosphate (?) is unprecedented/unknown to me otherwise... and to lose what appears to be such a tough species of fish so easily in the face of the other livestock you list... anomalous to say the least. I would ask for at least partial credit or be shopping elsewhere. You are welcome to forward, show my opinions to your dealer. Bob Fenner>

Just a few Questions before the New Year Bob, Thank you for your help in the past. You've helped my system become more healthy. Have a happy new year tonight as well. <You as well my friend> I have a FOWLR 40 gallon at the moment(35# of LR), and going to make it reef with a few fish when comfortable to do so. I have two blue damsels, two Talbot damsels, <A very nice fish for aquariums> one domino damsel (they are all 1") <Watch out for this bad boy> , and an adult convict blenny (about 12"). 192W of PC lighting, skimmer, hang on filter for carbon and mechanical filtration. Here are my questions. Right now, I am feeding the fish small amounts of frozen Formula 1, and Prime Reef. I only feed them once at night, and it's kind of a pain to melt the food every night. I would like to supplement this with a flake or small pellet food in the morning.  <Yes, certainly> I looked through your FAQ's, but couldn't find any certain brands that you recommend. Does brand matter? Any recommendations would be appreciated. <Brand, maker does indeed matter. HBH, Spectrum, Hikari, Omega One, most of Tetra's fine products are all excellent ones that I have first-hand experience with> Also, my phosphates were high about 5 ppm), <Yikes!> but have dropped to about 2 ppm over the last two weeks.  <Still too high...> Needless to say, I have some green algae on my live rock, not too bad though. If I eliminate the source of phosphates, will the algae go away after it runs out of phosphates? <Likely so. Phosphate is a rate-limiting/essential nutrient> (assuming my nitrates are low) I have used distilled water for water changes, and there are only two ways for these phosphates to enter my tank. Food or carbon.  <Mmm, and as livestock... and as part of decor, substrate... and recycled from all these sources> I had some activated carbon in my filter that was distributed by Aquaclear, but it's made by Hagen. Could this have been the source of the phosphates?  <Yes> I have since removed and replaced with activated carbon that is labeled phosphate free. By the way, I ordered your book The Conscientious...), and it will arrive in a couple of days. I look forward to it since it is my first marine aquarium reference. <You will greatly enjoy this experience.> Thanks for your help. Happy new year! Dan <Be chatting my friend. Bob Fenner>

Mollies Robert, <Steven Pro in this evening.> My girlfriend has a marine aquarium with silver and calico lyretail mollies in the tank and surviving quite well. She was mainly testing her water with cheap fish before purchasing more expensive livestock. It has been setup for a good 6 months with live rock and live sand. Not very many fish until recently. I'm sending you this because I was under the impression only black mollies were able to thrive in a marine aquarium? <No, any of the mollies will survive in full strength seawater.> Also, I've got a little bit of a algae problem with my main marine aquarium. I've tested my phosphates which are a staggering almost 5.0 ppm. <Yes, staggering is right.> I've been told that my non-use of RO water is contributing heavily to this. <Possibly, also over feeding and/or poor nutrient export processes.> However, when I test my tap water I have no trace of phosphates, that are very detectable anyway with my test equipment. (HAGEN). Is my problem with excess food and dying algae contributing to my excessive algae growth? <More likely the feeding.> I just have a problem with the excess food theory as I feed my food (live food) very sparingly. <Any food that is not eaten becomes nutrients for undesirable algae.> I've also been told my phosphates being so high will make non-invertebrate life almost impossible such as anemones. ...and every time I get a anemone it spits out its' guts within 24 hours or so. <Phosphate is problematic for stony corals and calcification, but more likely another cause for your lack of success with anemones. They are terrible choices for most home aquariums with a dismal track record.> Thanks for the help. -Bryan <You are welcome. -Steven Pro>

Mollies Follow-up I've just began trying SeaChem phosphate absorber. Have any luck with these products? <Not really cost effective even if they work. The RO or DI unit can remove much more along with careful feeding and aggressive nutrient export.> Haven't used it long enough to evaluate the results. Also, one of the things I've thought about in the past was contributing to my algae growth was excessive heat. I can't maintain my temp much lower than 85. I have one bulb on for about 7-8 hours a day on a timer. ...room temp is about 75 or lower at all times, any ideas? besides an expensive chiller? <If your room temperature is 75, you should not have such a high tank temperature. Try readjusting or get a new heater, vent your canopy, use fans to remove hot air, use fewer powerheads by installing a larger external sump return pump, etc. -Steven Pro>

Nitrates/Phosphates Good Morning - Bob, Steve or Anthony <Steven this afternoon.> I have a 29 gallon reef tank. The inhabitants are: 1- Yellow tailed blue damsel, 1- pink skunk clown, 1-long nose hawk and 1-flame hawk, 1 six-line wrasse as well as 2-large cleaner shrimp and 1 large banded coral shrimp, 1 large Turbo Snail, 4 other snails that just appeared and various mushrooms, polyps, leather corals and a colt coral. All fish and corals seem very healthy and have good appetites and corals are spreading. I feed once a day sparingly. My water conditions are: PH=8.4, Ammonia =0, Nitrite=0, Nitrates=10-20, Calcium=450-460, Phosphate=.25-.50, Alkalinity=125 which is what the test kit says it should be but I can't remember what that's measured in. <Alkalinity of 125 is not possible. It should be 2.5-3.5 meq/l or 7-10 dKH.> I change out 6 gallons of water per week. <Very good.> I have a SeaClone Protein Skimmer that skims 1/4 to 1/2 inches of skimming per day which I think is a little low. <I would like to see more skimmate, but may not be possible with this skimmer.> A Penguin 330 bio wheel with charcoal filters and 2 Hagen power heads ( I think they are 300's) with quick cartridges. The quick cartridges have a foam insert. I would like to keep my Nitrates down to zero but with fish, I wonder if that is possible. <With this current bio-load and filtration, it will be difficult. a DSB may help.> Would I be better off as far as Nitrate and Phosphate to remove the quick cartridges from the power heads and turn one of them upside down low and blowing into the rock ? Would this perhaps increase the efficiency of the Protein skimmer? <Not likely to increase skimmer performance much. Do be sure to clean and/or replace the cartridges fairly regularly, at least weekly.> I would like to achieve the best conditions I can for my tank size which I know is small. I am going to set up another 29 gallon tank on the bottom of my stand (wall space is an issue) and take one of the hawks and two of the other fish (wrasse/damsel and some of the corals and put into the lower tank once it has cycled to lessen the bio load on the tank. Is this a feasible plan? <Sounds good.> Any suggestions would be appreciated. <I would look at the Prizm skimmers from Red Sea. Considerably more effective and about the same price.> I can send a picture if you think it would help. <Not needed at this point. -Steven Pro>

High Phosphates and Nitrates Hello, I am posting this for a friend from my salt club, can you help? <I'll try> I have been having some water chemistry problems lately that I can not figure out, so I am going to put it out there for you all to help with. About 2 months ago, I started getting high nitrate readings along with moderately high phos. Everything I have tried to get these down has failed or only worked for a short time, which equals failed in my book. I have nothing missing in the way of livestock, most of my corals are now doing fine, with the exception of the birds nest frag I got at the swap. I have tested the makeup water and it does not read any nitrate or phos. either. Tank readings this am are. pH. 8.0 (buffer added), Nitrite 0mg/L, Nitrate >110 on one kit >120 on another, Phos. 1.0mg/L, Ammonia, 0 on both kits, KH 110, CA 300 (today is Kalk day). <Elevating the pH with the Kalkwasser to about 8.5 (temporarily, it will drop soon on its own) will precipitate out most of the soluble phosphate here... But its source?...> Tank is a 55 gal with 4-5in DSB, HOB BakPak skimmer, 4 Powerheads for circulation, Temp. remains at 78. Inhabitants: 2 tangs, 2 midas blennies, 1 blue damsel, 1 lawnmower, emerald and sally lightfoot crabs, 2 conch with multiple babies, 5 starfish of different varieties with multiple baby ones. About 70lbs LR, Multiple corals of all varieties (SPS, LPS, Softies). Coralline growth is great. No nuisance algae. I have been struggling with red Cyano, but it appears to be controlled now. <Here's a clue> Photo period is 14hrs, first and last 2hrs are actinic only from 220w pc lighting. Any ideas? Suggestions? <It may well be that the measurable nitrate, phosphate are coming from the dissolving Cyanobacteria... or perhaps a mineral source in the system (substrate, rock...), overfeeding... Please have your friend read through this section of our root web: http://www.wetwebmedia.com/nitratesmar.htm and the linked FAQs files there. Bob Fenner>

High Phosphates and Nitrates Hello, I am posting this for a friend from my salt club, can you help? <I will try.> I have been having some water chemistry problems lately that I cannot figure out, so I am going to put it out there for you all to help with. About 2 months ago, I started getting high nitrate readings along with moderately high phosphate. Everything I have tried to get these down has failed or only worked for a short time, which equals failed in my book. <Agreed. This type of problem needs to be attacked at the root cause, not by attacking the symptoms.> I have nothing missing in the way of livestock, most of my corals are now doing fine, with the exception of the birds nest frag I got at the swap. <Phosphate is a known inhibitor of calcification.> I have tested the makeup water and it does not read any nitrate or phosphate either. <Is this some sort of purified water, RO or DI? Either one is preferable to tap water.> Tank readings this am are pH 8.0 (buffer added), Nitrite 0 mg/L, Nitrate >110 on one kit >120 on another, <Indeed, quite high.> Phosphate 1.0 mg/L, <This will fuel nuisance algae, if not now, soon, particularly Cyanobacteria.> Ammonia 0 on both kits, KH 110, CA 300 (today is Kalk day). Tank is a 55 gallon with 4-5 inch DSB, HOB Bak-Pak skimmer, 4 Powerheads for circulation, Temperature remains at 78. Inhabitants: 2 tangs, 2 midas blennies, 1 blue damsel, 1 lawnmower, emerald and sally lightfoot crabs, 2 conch with multiple babies, 5 starfish of different varieties with multiple baby ones. About 70 lbs LR, multiple corals of all varieties (SPS, LPS, Softies). Coralline growth is great. No nuisance algae. <Surprising!> I have been struggling with red Cyanobacteria, but it appears to be controlled now. Photo period is 14 hours, first and last 2 hours are actinic only from 220w PC lighting. Any ideas? Suggestions? <Many possibilities. Over feeding, feeding inappropriate foods, inadequate nutrient export processes, not large enough or frequent enough water changes, etc. Not enough information given at this point for a definitive answer. -Steven Pro>

Alk/phosphate questions Mr. Fenner, <Hi Mike, Craig here today> I have a few more questions, I just tested the alk today (have been testing daily waiting for it to fall from high levels) and the reading was 4meq/L dKH was 11.2.  <This is good. Ideal range is 3.5 to 5 meq/L.> Up until now I suspended topping off the tank with Kalk, because of the previously high level. Is now a good time to top off with Kalk water?  <Kalk is a calcium supplement and does not directly affect alkalinity, but does optimize the system alk. It does have an extremely high pH (12) so should be administered at night to moderate pH fluctuations and dosed according to daily average usage of calcium. See Kalk faq's at: http://www.wetwebmedia.com/kalkh2ofaqs.htm >  Secondly, I suspended adding a buffer to my new water for the water changes, can I add the buffer too? The Ph was at 8.1 tonight. Will the buffer raise the alk drastically or more like maintain it as it does the Ph? <If using RO/DI water, aerate 12-24 hrs, test pH and buffer to 8.3 I use Seachem Marine Buffer and follow the dosage on the label. Add salt mix, run powerhead/aeration/heater for 12-24 hours. Should be 8.3-8.4 pH. PLEASE do figure average alkalinity usage as you do for calcium and dose the buffer/carbonate additives to maintain 3.5 to 5 meq/L alk.>  ---------------------------------------------------- The reason I ask the buffer question is this, I also have an algae problem, its brownish and covering over half the glass in the tank, and some spots of red algae. From an email I got here I heard a higher Ph level will help combat the high phosphate level (0.25ppm). <Kalk use will take care of this. Test calcium and dose Kalk daily to match usage. This is likely not phosphates, but diatom algae and Cyanobacteria. Increase circulation for Cyano and reduce nitrates and silicates for diatom algae. Lowering phosphates will naturally help. If this is a newer tank, this is a stage your tank will go through. Check your source water, make sure your skimmer and filtration is optimized, and remove as much as possible.> Here are the steps I'm thinking of taking: reduce the period of lighting from 12 hrs to 8hrs. <VERY bad idea if you have photosynthetic inhabitants you want to live. They need 12 hours. Will not reduce phosphates, silicates or nitrates.>  Adding the buffer to raise Ph. <Also bad idea. Add buffer to alkalinity test results. All else remaining normal this should provide a 8.3-8.4 pH. Adding buffer indiscriminately will raise alkalinity to abnormal levels.> Buying a chemical phosphate reducer. <Some of these are quite good. I like Polyfilters.>  Will any if not all of these help reduce the phosphate in the tank? <Kalk use, water changes with phosphate free source water, low phosphate foods, appropriate feeding, skimming, filtration, PolyFilter/chemical will all contribute.> Tank Parameters: amm 0 nitrite 0 nitrate 7-10 alk 4.0 meq/L (down from 5.5 yesterday, is this normal to drop this much overnight) <With calcium additives, yes. Test both alk and calcium on alternate days adding supplements for calcium and alk on alternate days until ideal range for each is attained. Test, write down results, stop additives for three days, test again, subtract and divide result by three. That is your daily usage of calcium (Kalk) and alkalinity (buffer). That's what you have to add of *each*, every day. Kalk at night.> dKH 11.2 Phosphate 0.25ppm Calcium 365ppm (up from yesterday's 330ppm, using reef evolution concentrate) <Yes, will drive alk down more so test alk and calcium while supplementing calcium.> Ph 8.1 <Likely AM test? Test in PM> SG 1.025 Temp 78F Lighting 12h/day Thanks once again, I really need to buy your book, Mike <Hope this helps Mike! Craig>

Re: alk/phosphate questions Mr. Fenner and Company, It's Mike again, a few more questions.  <Hi Mike> Today I tested the Calcium and it was a 335ppm, down from 365ppm yesterday...does this seem likely or just an erroneous test yesterday?  <Yep. That's likely your calcium use for one day. Clams, SPS, LPS, etc use more calcium and adding alk will use some as well.> And one more algae question. You guys suggested I have diatom algae present in my tank, I scrapped the glass off and it looks clear, hasn't grown back by the barrel full yet.  <Yep, likely diatom algae> Now today I noticed some small green hair-like algae growing on my live rock, so I asked another friend of mine into reef tanks, he said get rid of it quick...it will take over a tank fast! Is this true and cause for concern?  <Yes, it can and will spread if you don't pick and pull it now. some Tangs eat it, but usually only when short. Best to do away with it before it gets going.> I have some margarita snails (3), some Cerith (3), and some scarlet reef hermits (10), and Nassarius snails (15). Will any of these aid in the control of this? And what type of algae could this be? <Not usually. This is green hair algae of course! Look up algae and specific ally green-hair algae on WetWebMedia.com for other possible controls.> After reading your reply below, I'm going to start topping off with Kalk water, and that Ph reading (8.1) was taken at around 7:30pm here that's why I wanted to dose Kalk to maybe raise it without the buffer. and if I understand you, Kalk doesn't effect alk reading? then I shouldn't have suspended it as I did. Thanks once again, Mike <Right. It reduced your calcium and didn't do anything to your alk. You can add buffer/carbonate up to 5 meq/l alkalinity, (which will likely produce an 8.3 pH), but using Kalkwasser will help with keeping the pH up as well. Make sure you test your alk regularly and also magnesium with Kalk use as it will be depleted over time with Kalk. Hope this helps, Craig> 

Knocking Out A Mysterious Phosphate Problem Hi Scott, <Hello again!> Thanks for such a quick response. <Glad to help!> I've been soaking stuff and testing water most of the day and it looks like you were right on the money. I tested the powdered bacteria and it had a reading of between 0.1 and 0.25. I had enough bacteria in a 2litre jug as I would put in a 60g tank so I'm not sure if that was the problem. On the other hand the crushed coral (which I rinsed well before hand) had a reading of 1.0. I'm going to get rid of the crushed coral but I was wondering what would you suggest to use to treat the problem, or will it work  itself out of the system once I have removed the source of the problem. <Well, phosphate can be exported or reduced by the use of chemical filtration media designed to do the job, but it will be such a tedious exercise if the cause(s) are not eliminated. I certainly would not use the bacteria product again. The substrate issue is obviously a tougher one to handle. I'd consider continuous use of phosphate reducing media for a while to see if the levels are reduced. If they do not go down, or if they continuously rise after you stop using the media, it may be worth considering the removal of your substrate and going with something that won't leach phosphates, such as many of the oolithic aragonite products available.> Thanks so much for your help, for a beginner to marine aquariums I was getting very disheartened by this problem. Thanks again - Ryan <Never give up, Ryan. Problems like phosphate are usually among the easier ones to solve. Find the source, and act to eliminate it! Good luck! Regards, Scott F>

Corals and phosphate problems? Hi WetWebMedia, << Blundell here. >> As is custom, here is your praise before the question.  You have  helped me a handful of times when I truly needed it, and you answering any  questions is the most appreciated thing. << You don't need to praise us, we're just here to help. >> I wrote last week with a general problem, it was screaming  "phosphate".  All my corals were retracted, and I had a serious red slime  problem.    I have since added 2 phosphate sponges. I did a 25% change  last week with barely noticeable effects.  I did a 100% water change( not  really 100%, it takes a half hour to siphon the water, and I add it back  gradually).  After this, my frogspawn opened completely, and my flower pot  is showing its polyps (about 10% protracted).  Generally I got a good result  from the massive water change.     My concern is my Xenia. It was thriving beyond belief-  it was almost 12" long, and its stalks were thickening. Almost 2 weeks ago, it  shrank to almost nothing, << Xenia is the first thing affected by change in most tanks.  Which is rather odd, since it is the hardiest thing in most tanks. >> I almost cant believe its stalks shrank to the point  where it takes up almost no area on the rock it came on. Its tips turned a  slight white prior to the water changes, but its color is back,     I won't bore you with chemistry, it is all well within  the recommended range. Briefly - ph, salt, amm, trite, trate, alk, calc-   8.2, 1.0235, 0,0 , 0 , 9.5, 475, all respectively.     I had briefly used city water (RO fitting broke) for 2  10% water changes. I let the water sit for a week before mixing salt.  All  my fish are happy as pigs in poop. << Wow that is happy. >> I really need some suggestions. The rest of  my corals responded well to the massive WC. The tank is 90 gallons, and until 3  weeks ago, never had even the slightest problem. I started the tank in March 2004, and I do not want this problem to become  a plague. Some more added info- 320 watts P/Cs, 650 gph sump return, powerheads circulate 1800 gph, SeaClone skimmer, 5 pounds crushed LR in the sump.    I am concerned for the tank, and would take to task any and  all suggestions you may have. << I'm not sure you need advise.  You did the big water change, and things are looking better right?  I'd keep skimming, and just give it time. >> I thank you kindly for your advice, both now and in the past. James Pruefer, Providence, RI <<  Blundell  >>

Phosphate problems Hello, << Blundell here. >>     I have been having an issue with phosphate levels in my tank.  It is an 80 gallon all glass with a 2" plenum of crushed coral and aragonite covered by about an inch of live sand.  I purchased it used so I do not know if the plenum was correctly constructed (I have sent an email to the old owner asking about the set up).  I was wondering if a plenum could go sour and be leeching phosphates into the tank?  << Nope... well I guess it is possible, but I'm sure that isn't what happened.  Plenums rarely go bad, and when they do phosphate isn't the problem. >> I have changed the micron bag in the sump and gone as far as replacing the old tainted live rock (it was plagued with algaes of all sorts).  I have added a refugium with Chaeto and do weekly 5 gallon water changes.  Please help! << Hmm, well water changes (like a 25% change) are always good.  Otherwise, growing macroalgae in the sump is the best way I can think of to remove phosphate.  There are commercial product phosphate removers, and many people really like them. >> <<  Blundell  >>  

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