[CaseyH]

Hey,

Hoping you all might have some help and suggestions to offer. I have a problem with too much calcium in my tank. I have verified w/ multiple test kits (and my LFS) and the level in my tank never drops below 650 ppm.

I have 5 stage RO source water and it also never goes below 650. My tank is a 46 Gal with skimmer, sump, wet/dry, Fluval 404, denitrator, phosban reactor, metal halide lighting, 65 lbs fiji live rock, live sand and healthy fish. Tank has been running for over three years and this problem has never gone away. I do not add any calcium supplements.

Corals (except Brown button polyps that are fine) do not last more than a few months at best. This includes anemones and clams as well. Any ideas?

Thanks!:confused:

[RyanG]

Have you tested your source water that is going into your RO filter? Your water might have high calcium to begin with. Or it might be things in the live sand that are making your calcium climb. What do you dose with every day, week, etc.?

[CaseyH]

Do they make a calcium test kit for fresh water? I know the water where I live is hard water. I thought RO would take care of that. I generally dose with Iodine and Strontium/Molybendum weekly. I have used Reef DNA but got red algae blooms. Also, I forgot to mention in my original post that I use CoralLife sea salt.

[RyanG]

Strontium will cause your CA levels to creep up. How long has this tank been up and running?

[CaseyH]

Tank has been up for just over three years. It's funny but the calcium levels have pretty much always been 650ppm since I began testing for calcium. It has never tested lower than 600.

[RyanG]

My next educated guess is that your substrate or rocks are helping your CA levels to rise. Try stopping with the Strontium/Molybendum dosing. Also what test kit are you using? You might be getting a false postive reading.

[CaseyH]

I have the Red Sea kit at home and my LFS tested with the higher end kit (I can't remember the brand?). I will stop the dosing for the moment and see what happens. I also think I have been running my SG way too high (32/1.0235) and am slowly bringing it down to 30, hoping the calcium will come down as well. I read somewhere that 32 was good number, but most of my fish are of the Indio-Pacific variety: Opercula Clown, Marine Betta, Purple Pseudo, Blue Damsel, Coral Beauty. I am going to see if I can find way to test RO fresh water for Calcium. Thanks so much for the help!

[coralreefer]

CaseyH,
You do not mention what the pH of your water is. If you have a low pH, the H+ ions will react with any carbonates in your tank. This will liberate Calcium in soluble form. I test freshwater calcium using versenate powder and reagent grade EDTA (the same EDTA is used as a food preservative).If the source of the Ca is your freshwater you can test for this by using a sample (100ml) of your replacement salt water before adding it to your tank. Mix baking soda into the sample in small amounts (use a paperclip that is flattened on one end). After each baking soda addition, agitate vigorously and allow sample to set undisturbed for a few minutes then retest the sample. If this technique lowers the pH too much, use sodium carbonate. The chemistry is almost identical, the sodium carbonate will not reduce the pH but the reaction will take longer in your test sample. IF YOU USE TOO MUCH OF EITHER OF THESE SODIUM COMPOUNDS YOU WILL DEPLETE THE REMAINING CALCIUM! A little goes a long way. You may find it easier to dispense the baking soda or sodium carbonate by dissolving them fist in fresh water before adding to your test sample.
If your makeup water is the source, try using a membrane in your RO with a smaller pore size. Hope this helps without overwhelming you with a chemistry lesson.

[SweeTang22]

yeah so that seems like alot of work lol. i would have started with the smaller pore membrane first lol. you seem very good with chem. are you a major or a teacher, or just very smart? i must say, im a bit jealous

[coralreefer]

I work as a chemist in the oilfield. The majority of my work is testing water for the same properties as you check in salt water. Alkalinity, calcium, salinity, chlorides and phosphates are where I make my money. My labwork is done on the tailgate of my pick up truck. The only difference is that I use grams in my fish tank and tons on the job.

[henwayrob]

have you ever tested your alkalinity, if it is low your ph will be low and your calcium can be high, there is a balance between alkalinity, calcium, magnesium in the water. here is a link to a good article at Chemistry and the Aquarium

[kolokefalo]

I would suspect a low PH causing it.