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FAQs on Marine Alkalinity Sources

Related Articles: pH, Alkalinity, Marine Alkalinity, Understanding Calcium & Alkalinity,

Related FAQs: Marine Alkalinity 1, Marine Alkalinity 2, Marine Alkalinity 3, Marine Alkalinity 4, Marine Alkalinity 5, Calcium and Alkalinity, Phosphate& FAQs on Alkalinity: The Science of Alkalinity, Importance, Measure, Use of Additives/BuffersTroubleshooting/Fixing, Products by Name & FAQs on pH: Importance, Science, pH Measure/Test Gear, pH Controllers & pH Buffers/Buffering, pH Anomalies (Troubleshooting/Fixing), & pH Products by Name, Manufacturer,

Bicarbonates alone will not elevate pH to NSW levels... carbonates are necessary... Mmm... from substrates, rock, seawater components, tap/source water, additives, foods to an extent... And leaving by: "things" that drive down pH, bio-accumulation by biomineralizing life... of many kinds

KH is high   2/26/11
Hope all is going well. I am having an issue with the KH in my reef tank.
My tank is 100 gallons stocked with Sps some lps and one xenia. I do 10% water changes bi weekly but no matter what my kH is always above 12 DKH. I tested it earlier today and it was at 13. What the heck do I do to get it down.
<Mmm, you need to discover the source of carbonate hardness is here... Your source water? Salt mix? Some soluble portion of your substrate, rock, other decor? You can test for each...>
My CA is always between 400-450. and the Mg is at 1250. everything is still growing but some of them are losing there color but not their polyps.
Thank you,
<Please read here: http://wetwebmedia.com/alktrbfix.htm
and the linked files above for background. Bob Fenner>

Alkalinity question Hi, <Hello there> After tracking down why my corals have not be opening all the way, I have determined my Alk is way too high. It is easily over 16dKH. I have been trying to determine the source and figured I was adding to much buffer to my make-up water. <Very common> That may be part of the problem, but not the real problem, I think. My RO/DI water measures 0-Nitrate, 0-Nitrite, 0-dKH, 7.6PH and 25ppm Hardness. Seems ok, right? <Mmm, no... there are some such water treatment units that allow carbonates, bicarbonates through, but not many... your hardness should be much lower> After I mix the salt (IO reef crystals) and raise the temp... about 24 hours later my dKH and hardness are off the charts?? It seems as if the RO water is super sensitive to adding any amounts of buffering, even the built-in salt buffers. I have been doing large water changes to try and balance my tank out... but if I am starting with high Alk. I am not sure what to do. Do my filters in the RO/DI need replacement? Can I lower the Alk in any other way?  Thanks for any suggestions. -Brian <I would have your alkalinity test gear tested... check your water against some other assay, perhaps seek out samples of water with known KH, GH to test your tester... AND seek out what other sources of hardness may be influencing your readings... Do you have new substrate in this system? Of what composition/origin? Lots of new base rock? Something simply is awry here... and we will find it. Bob Fenner>

Re: Alkalinity question Hi Bob, <Brian> Thanks for getting back to me. Very good diagnosis, because yes I actually do have a new substrate or at least some of it. <Ah ha!>  My whole problem started with high Nitrates a few weeks back, so I doubled the sand bed from 2" to 4" (Southdown sand that I stocked piled when it was available). My Nitrates are down considerably with large water changes in effect until the sand really kicks in, I am sure it's helping already. I have noticed this high dKH problem ever since the increased sandbed or at least that's when I really started monitoring all parameters. Sounds like the new sand could be the cause? <Yes... the more easily soluble portions are dissolving...> If so, I assume it will stabilize over time? Thanks so much!  -Brian <You are correct here... weeks to a few months. Bob Fenner> 

Succeeding with reefing: follow-up Anthony, Mark here. We were talking around Thanksgiving about some water quality issues and my tank of tangling tangs. <Yessuh> I started using a two part calcium and buffer system and it has worked wonders. <totally tubular to hear> Calcium level at 420, PH 8.4, and alk finally came up to 8.5dkh. Thank you so much for all your advice. <very welcome> I also realized something else that was causing my dilemma. My top off water which I never used to buffer) had a ph of below 7.7 and an alk that was so low it wouldn't even measure. <yep... that would be a problem/burden on ALK> I'm sure this was a key part to my problem. I also got an adjustable air valve for my skimmer which has made it work 10 times better. All my corals look much healthier now and my Turbinaria has polyp extensions like none that I have ever seen. I really appreciate all your advice, and I will not add any more tank mates until I get my big tank. <very cool... and I'm sure all will fare better for it> One more stupid question though. When I do a water change is it necessary to buffer the salt water also? <depends on the quality of the source water you start with. If your freshwater is demineralized (RO, DI, distilled)... then you definitely have to buffer> Or does the salt mix set the ph and alk where it is supposed to be. <salt mixes generally do have at least a little extra buffer> Thanks again and hope you and yours and everyone at WWM have a wonderful holiday season......Mark <and the same to you my friend>

That Time of Year... Depressed pH - Well-insulated Houses - 8/14/03 Hi, <howdy!> Have been researching the salt mixing process on your site, and have seen reference to buffering the RO water, prior to mixing salt, but could not find more specific details. <it's not rocket science, mate... we use RO or DI to demineralize water for the removal of the good and the bad. Then, simply buffer back with the good to a medium high/hard ALK and pH within the known safe ranges of seawater. Thus ensuring very consistent water every time (versus variable tap water quality)> Currently before mixing the salt, I leave my water to aerate for a day with a heater and powerhead in it, <very good> after which the PH tests at 7.4 prior to mixing the Instant Ocean. <not bad> Should I buffer this water prior to mixing? and if so, could I use my normal buffer, Seachem marine buffer? <yes... just a little would be fine to get closer to 8.0 or so> I am struggling somewhat with low PH in the tank, ranges from 7.9 to 8.2, and wonder if there is something I could be doing better.  Thanking You, Alastair <very common this time of year because of well insulated houses (depressing pH from excess CO2 in the house/water). Confirm this problem by taking a glass of aquarium water outside and aerate it heavily for 6-12 hours. Test pH before and after... there should be no change... but an increase would indicate the above problem. Much has been written on this topic in our archives at wetwebmedia.com if you care to read it. Best regards, Anthony>

Establishing Calcium and Alkalinity <Hello! Ryan with you today> I have a 58g reef tank that I started about  2 months ago.  I have 70lbs of live rock, 40lbs live sand, 2 clownfish, 1 Kole tang, 10 snails, and 5 crabs. <OK> I have a Euro-Reef cs6-1 skimmer, 250w 10,000k metal halide light, 450gph sump pump and 300gph circulation pump.  I've start thinking about adding calcium to my system to get ready for corals and I can't decide which method to use. <Understood> I'm thinking Kalkwasser, 2-part calcium/alkalinity, or Seachem reef advantage calcium. <B-Ionic 2-part calcium alk is what I prefer> I'm looking for least maintenance, most idiot proof, and most effective. <Exactly why I prefer it> I would also like a recommendation for inexpensive test kits for calcium and alkalinity. <Seachem works well and is reasonable> What are your thoughts on the calcium situation and what are your thoughts on my setup so far? <Sounds great, you've got sturdy equipment list and you're taking it slow.  I'd add some live rock if possible, you'll want at least 1 pound per gallon.  Best of luck! Ryan> Your help is much appreciated.  Thanks,  Chris

- Alkalinity and Concrete Rock - Hi there Crew, Clayton here; <Good morning, Clayton.> Here is a brief rundown of what I am up to, first of all, I had a cloudy water problem that no amount of advice from anyone seemed to be able to cure so I dumped all my water and set it all up new, I used instant ocean salt and RO water for everything, the tank is 240 gallons with a 30 gal sump, with a Berlin xl skimmer, 2 x 400 W MH and 2 X 40 W actinic blue and 2 x 40 W trichromatic, so here is what I did, when I took my tank down I left it down for a month or so because I also changed the front glass, but in the mean time, my crushed coral I had in 5 gallon pails began to rot or something because the pails were still like half full of water,  so to clean it I rinsed all the crushed coral with bleach, and then rinsed the crushed coral excessively, and also added about 100lbs of aragonite sand, under the advice of the Local Pet Store I installed a "plenum" or so he called it, which is basically a undergravel filter that is not hooked up to anything to promote anaerobic bacterial growth to reduce nitrates or something like that anyway, I do not have too much Live Rock, only like 50lbs or so, the rest is some sort of homemade concrete stuff made by a fellow aquarist, but my problem I have with my alkalinity is that I cannot get it up to the normal level and keep it there, in the past month I have added basically a whole container of SeaChem reef builder, (for raising carbonate alkalinity) which is 1 Kg or 2.2 lbs but every time I add this stuff my alk goes up to about where I want it, like 120-130mg/L (or ppm) but within a few days it is back down to 70-80 ppm, it just does not stay up, my calcium is also unusually high it is like 650ppm which I think might have something to do with it, but I have no Idea what or how to fix it, my PH is also low, steady though at 8.0, however the fish are doing great, and the corals I have are spending 90% of their time closed, except the mushrooms however, which seem to be loving it,  and polyps are also doing fine (other corals are soft leathers) however I also tried to introduce my brittle starfish back into my tank and within the 2 days I kept it in my tank, it didn't move around and one of its arms fell off, and I also go a banded shrimp which looked like it was doing fine, it was eating and running around lots, then one day was dead.  Please Help,   Thanks <If I were to pick out one thing, I'd examine that concrete rock. Concrete rock [and even formed blocks] must be soaked in saltwater for months before it can be used in your tank. When it is new, it can do wacky things to your water chemistry so it must be 'cured' [not the same curing as live rock] and rinsed and cured and rinsed before you put it in your display tank. I suspect that this is the root cause of your troubles... I'd be willing to bet that everything else stems from that. Ask that aquarist if he cures the material and for how long - I suspect that if he has cured it, it hasn't been for long enough. A pH of 8.0 is too low and while some animals 'seem' to be doing fine, you can expect them all to have troubles if exposed to this pH for any length of time. Cheers, J -- > High alkalinity 12/17/03 Hello Anthony! <cheers, Thanassis> I have the following problem: my Alkalinity has been about 11-12 dKH and I have not been able to measure the Calcium because of faulty test kits. <the alkalinity is fine at this level my friend... no worries. 8-12 dKH is a safe range> I have been adding water from an R/O unit , aerated and buffered it with baking soda before I add it to replace evaporated water (about 3 liters/day). I add also 20 ml of B-ionic once a week. The tank is 300 liters and I have coralline algae and Halimeda growing in it. No corals yet, only a Zoanthus sp. Yesterday I measured the alkalinity and it is 18 dKH! I suspect I have been adding too much soda in the water. <yikes... yes. It does seem so> With such a high alkalinity the calcium is prevented from being present, isn't it? <correct> How can I drop the alkalinity to 10 dKH? What can I do about my calcium as long as I can not measure it?  Thanks, Thanassis <water changes to dilute the problem and supply calcium are recommended here. Small frequent water changes are always better than larger less frequent ones. I suggest weekly 10-20%. Anthony>

Alkalinity Quick question? <<Sure...>> It seems I have to add about 1 teaspoon of baking soda or SuperBuffer to my top off water every day to keep my alkalinity around 10 to 12. <<By any chance is your top-off RO/DI water? This is pretty typical if so... RO/DI is demineralized.>> Is that o.k. or am I adding to much to the system. <<Probably fine... do be careful about bringing up the alkalinity too high. I wouldn't go over 12.>> I have been doing daily testing and it has never gone over 12. <<There you go then.>> Thanks <<Cheers, J -- >>

Depleting Alkalinity & Calcium Hi Bob, Once again I am seeking your help and expertise on a continuous and disconcerting problem I have with maintaining alkalinity and calcium stability. A Drastic depletion occur on a daily basis (alkalinity drops approximately 0.2 to 0.3 meg/L per day and calcium drops approximately 20 ppm per day as well). <Not unusual circumstances in "boosted photosynthesis" tanks... biomineral, alkalinity being used... rapidly> To combat this problem, I am currently performing 5% weekly water change, <May need to increase this... maybe to ten percent> dripping R/O water mixed with baking soda to elevate alkalinity (saw the suggestion on your website, although it appears to be a temporary solution) <Yes, and just a stop-gap measure> , and administrating ESV calcium directly into the tank every other day. I am very concern with the rapid depletion of elements and any suggestion/information to rectify my problem will be greatly appreciated. <In two words: calcium reactor... saw twelve Knop reactors (Hey Daniel, you owe me schnitzel!) at a friends LFS yesterday...> Below is a list of my current livestock inhabitants, water parameters, and filtration methodology in a 90 gallon tank (recently converted from a F/O tank): Fish: Majestic Angel---doing great and thriving for 8 months! Yellow Tang Invertebrates: 3x Cleaner shrimps 24x Turbo snails 12x reef hermit crabs 1x Wellsophyllia 1x Finger leather 2x Cynarina 3x Mushroom Water Parameters: Ammonia = 0 ppm Nitrite = 0 ppm Nitrate = 10 ppm pH = 8.2 Salinity = 1.025 Alkalinity = 2.8 meg/L (drops 0.2 to 0.4 meg/L per day ¦YIKES!) Calcium = 340ppm (+/- 20 ppm)---similar drop compared to alkalinity'¬Â¦approximately 20 ppm per day (double YIKES!!). Filtration: Wet-dry ETS protein skimmer 100 pounds of live rock---thinking about adding ~ 20 to 30 pounds. 40 pounds Aragonite sand Miracle Mud Ecosystem by Leng (recent additional'¬Â¦hopefully will help with water stability). Supplements: ESV (2 parts calcium and alkalinity) Kent Trace Elements Kent Iodine (drip methodology---weekly) Kent Iron/Magnesium (drip methodology---biweekly) Kent Strontium (drip methodology---biweekly) Additionally, can you please give me any recommendations with the usage of supplements (frequency, quantity, and product); I am not getting the desired results especially with the Kent products. <These are good products, in a good line... entirely miscible, no bad interactions... Would look into Tropic Marin's BioCalcium product if you are going to stick with the rest of the Kent's line... But do strongly encourage you to look into a calcium reactor... the simplest, easiest, safest, and least expensive-in-the-long-term method of maintaining/optimizing pH, alkalinity, biomineral content. Bob Fenner> Thank-you for the time. Regards, Dan

Aragonite i have a 75 gal trickle overflow with a 20 gl sump that is large enough to handle a 15 tank and is working good water spec are great the only problem i have is that my ph stay at 7.9 or 8.0 i add Kalk by slow drip but after the one gal bottle empties it goes back to the 7.9 - 8.0 i would like to know if the original aragonite that i put is the tank eventually loses its punch  <All substrates do> or maybe i don't have enough  <A distinct possibility> got about120 lbs live rock i got about an half inch under the rocks and about one inch and a half in the front of the rocks fine to med grain should i had more and if so how much do you think this would help i have a med to heavy load of live coral and about six small fish would increasing the amount on the bottom be the solution THANKS <Maybe... but look into more of your background in water chemistry here... You'd be better off with a "two part" supplement system to bolster your alkalinity (give up the Kalk)... and best with a simple calcium reactor. Please read over these areas on our WWM site, starting here: http://www.wetwebmedia.com/watrqualmar.htm and onto the many linked files, FAQs listed. Bob Fenner>

Adding Buffer or Calcium? Anthony, <Cheers, John> Thanks for the clarification. Only problem is that I too have a reef system albeit a small load right now of a Pinked Tip Anemone, Hammer coral, feather duster, serpent star, star fishs etc. and about 90 lbs of live rock. Everything is doing quite well, but maybe I should not do the baking soda thing? <really two different things and purposes. Baking soda is largely for increasing pH (tweaking pH in an otherwise normal/healthy tank with other buffers/carbonates as one gets from med/hard tap water). It is easy to use and monitor. If that is your primary goal and you are using tap water (not demineralized R/O or DI water) than please use the baking soda at the prescribed CMA dose. If however, an aquarist IS using purified water (lacking buffers) and/or has a known deficiency in alkalinity in the water (naturally soft tap water for example) then sodium bicarbonate alone will not serve a reefkeeper well. Most commercial buffers (like Aquarium Systems Seabuffer) are "tri-buffers" (borate, carbonate and admittedly mostly bicarbonate) and better suited for increasing and maintaining pH (from the baking soda) as well as ALKALINITY (the buffering ability of water). If you haven't had the displeasure <smile> yet of studying the difference between pH and Alkalinity, then this may be part of the confusion. Back to the "story"... reef aquarists generally want/need to put buffers AND calcium into their system and neither one alone (baking soda or Kalkwasser) will usually do the trick. I hope this hasn't confused matters further. Please do follow up if you need clarification. Nonetheless... the bottom line is that hard tap water may not need to be buffered, and baking soda will give you the extra pH you need... and purified water is not buffered, and needs something more than just bicarbonate. Kind regards, Anthony> John

- Lowering Alkalinity, Follow-up - Hi and thanks for the reply. <My pleasure.> I have been using the same Tetra Test for several years and test exactly the way you have suggested. <Hmm... perhaps time for some new reagents.> I have always tested my change water for pH, alk and salinity before changing.  I use Instant Ocean and the alk usually tests around 14-16 dKH. <Have heard many reports of late of high alkalinity when using this salt... perhaps they have a wacky batch out there.> The pH of the change water is always around 8.3-8.4.  I have never tested my source water for alk but will now. <Worth checking.> Any other suggestions if my source water is high as well? <You may want to try and deal with this at the source, before adding salt. The process is a little time consuming and potentially hazardous if you go about it carelessly. You can use a weak acid, like vinegar... but is not wise to add wholesale. Rather add in small amounts and then test... wait a half day to a day and then test again. And go through this process a couple of times, testing and adding more acetic acid in very small amounts. Do not add the vinegar directly to your tank, and I'd try to avoid doing this to mixed water as well.> Anything else I should look for/do? <Start at the source.> Thanks again, Jeff <Cheers, J -- >

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