Elevated Calcium Level

[zpete3323]

Hello all! I am currently trying to reduce my calcium levels on my frag system as they have been creeping up for the last month or so. Trident tests x4 per day x2 being alk only and x2 being alk,calc,mag.

Current levels are:
Alk - 8.2-8.3dKh
Calc - 560-580ppm
Mag - 1200-1250ppm
~500g water volume

I am starting to see some precipitation of calcium and spent the last weekend cleaning everything up once again.

Typically I dose alk using an icecap kalk reactor at around 6L per day. I have since dropped this down to 2L per day and dosing 50ml of red sea alk instead to try and not introduce as much kalk into the system. No changes as of calcium levels have been seen in the last 7 days of this alteration. Only other additions to the tank for dosing are 10-20 drops of iodine/week and 20ml/day of Pohl's Xtra Concentrate.

Recommendations?

 

[mtraylor]

Personally I wouldn't do a thing. I used Oceanic salt for many years and it would mix at 520-580ppm right out of the bag. Loved the stuff and kept corals going. If you have stopped adding so much calcium then the corals should consume it and level out where ever you need it. I like my calcium high to ensure growth.

 

[Randy Holmes-Farley]

Kalkwasser will tend to raise calcium over time if used to maintain alkalinity because it is overbalanced in terms of calcium dosing relative to alk. In your case, using just the alk part to replace some of the kalkwasser is a fine plan.

This is from an older article of mine that explains how I handled it:

Calcium (Ca). In my reef aquarium, I use only Instant Ocean salt and I have not added any additional calcium except as limewater for a number of years (during which time I have continued regular 1% daily water changes). So why is my calcium level (472 mg/L) higher than one would normally expect for Instant Ocean (maybe between 350 and 400 mg/L)? That long term rise in calcium is actually the expected result when using limewater to maintain alkalinity.

Limewater adds calcium and alkalinity in exactly the same proportions as in pure calcium carbonate. So if that is what is used by corals to make skeletons, and what precipitates on pumps and such, then calcium would stay constant.

But both magnesium and strontium get into growing calcium carbonate crystals in place of some of the calcium. A few percent of the calcium is replaced this way. Consequently, since the same amount of alkalinity (the carbonate) is used over time, and somewhat less than the balancing amount of calcium, calcium rises if alkalinity is maintained. I’m happy to see the result match the theory, and the calcium level seems fine to me.

 

[zpete3323]

Kalkwasser will tend to raise calcium over time if used to maintain alkalinity because it is overbalanced in terms of calcium dosing relative to alk. In your case, using just the alk part to replace some of the kalkwasser is a fine plan.

This is from an older article of mine that explains how I handled it:

Calcium (Ca). In my reef aquarium, I use only Instant Ocean salt and I have not added any additional calcium except as limewater for a number of years (during which time I have continued regular 1% daily water changes). So why is my calcium level (472 mg/L) higher than one would normally expect for Instant Ocean (maybe between 350 and 400 mg/L)? That long term rise in calcium is actually the expected result when using limewater to maintain alkalinity.

Limewater adds calcium and alkalinity in exactly the same proportions as in pure calcium carbonate. So if that is what is used by corals to make skeletons, and what precipitates on pumps and such, then calcium would stay constant.

But both magnesium and strontium get into growing calcium carbonate crystals in place of some of the calcium. A few percent of the calcium is replaced this way. Consequently, since the same amount of alkalinity (the carbonate) is used over time, and somewhat less than the balancing amount of calcium, calcium rises if alkalinity is maintained. I’m happy to see the result match the theory, and the calcium level seems fine to me.

Randy thank you for the thorough reply! I was hoping that my transition to alk only would help some but I am happy to see that I shouldn't be as worried as I am about the high levels.

I use tropic marin pro-reef salt and have been seeing higher calcium and alk around 7dKh. I will see what the future brings and potentially swap salts if necessary. Thank you!

 

[Randy Holmes-Farley]

Randy thank you for the thorough reply! I was hoping that my transition to alk only would help some but I am happy to see that I shouldn't be as worried as I am about the high levels.

I use tropic marin pro-reef salt and have been seeing higher calcium and alk around 7dKh. I will see what the future brings and potentially swap salts if necessary. Thank you!

You're welcome

Keep us updated on how things progress!