High calcium usage?

[IOnceWasLegend]

So I've started testing every day to dial in calcium and Alkalinity usage for dosing. I've been testing every day at the same time, and so far my tests indicate my system's using 0.5 dkh and 40 ppm calcium every day.

That calcium usage seems like a lot (especially compared to alk), but I also have coraline algae starting to come in and a lot of LPS. Just wondering if that's normal or a potential issue.

 

[Coral reefer]

Seems like a lot to me. What are you testing with?

 

[rygh]

What is your Alk and CA levels?
Could be precipitating out.
Keep an eye on your pumps and other equipment for calcium deposits.

 

[IOnceWasLegend]

Seems like a lot to me. What are you testing with?

API calcium, Hanna alk checker

What is your Alk and CA levels?
Could be precipitating out.
Keep an eye on your pumps and other equipment for calcium deposits.

Yesterday: 8.8, 500

Today: 8.3, 460

 

[Newjack]

i wouldn’t trust the numbers you’re getting for cal. If you are gonna start dosing an alk. solution, i would just dose calcium in an equal amount. ex. if you tank needs 20ml. of alk solution, then dose 20ml calcium solution. The tank should balance itself out.

 

[RandyC]

API calcium, Hanna alk checker



Yesterday: 8.8, 500

Today: 8.3, 460

Is this consistently happening daily or is the first time it’s happened? A 40ppm drop would be pretty insane. The ratio of calcium consumption is around 18-20ppm for every 2.8 dkh of alk (according to Randy Holmes Farley). I’d suspect potential testing errors first, then precipitation second. But I’d heavily lean on the former to being the problem.

 

[Meshmez]

If I remember correctly, the api cal test goes in increments of 20 ppm, and the color change can be somewhat hard to detect exactly. So in my opinion there could be a couple drops difference in color change interpretation.

As others mentioned dose the same amount as whatever you need for alk.

 

[rygh]

The things I can think of:
1) Test kit errors.
2) Calcium precipitation.
3) Coral growth.
4) Adsorption my other media, like GFO lowers Alk.
5) Water changes with poor salt mix
6) A slow leak or significant over skimming

Questions:
What is your setup? Gallons? Sump?
Are you running GFO or some other media? Algae scrubber? Anything?

Suggest:
1) Have someone else test the water with different test kits.
- for test errors
2) Check your salinity with a calibrated refractometer, make sure that is not dropping. Do not trust Apex.
- for slow leaks/skimming
3) Test magnesium
- for precipitation