Unable to increase calcium levels

[Randy Holmes-Farley Verified Community Expert]

That’s the question.

I think I was overdosing sodium carbonate (alk got to 10.3). Maybe a lot of the calcium was precipitating out?

Magnesium was running high at 1550-1600 as well. But my understanding is that that would compete for binding sites between calcium and carbonate, not lower calcium… ?

I clearly need to test calcium more frequently. Thought I had the ratio somewhat dialed but it’s likely way off.

Yes, that could do it. Any dosing of alkalinity not accompanied by calcium has a tendency to lower calcium.

 

[West1]

Yes, that could do it. Any dosing of alkalinity not accompanied by calcium has a tendency to lower calcium.

Interesting point. Is there a specific time frame Ca should be dosed after Dkh to prevent lowering Ca?

 

[scotty333]

Super old thread but I have a bigger problem, my calc was low at 320 so I dosed it up according to the instructions and it just raised 5ppm so I put 5x the amount and it shot up to 680
So I started doing 20% water changes and tested at 325 , then 300
The Red Sea salt mixes at 400 and I’ve checked this with my kit and it’s accurate, also had the lfs check with same results
Question is … where’s the calcium gone?

 

[Randy Holmes-Farley Verified Community Expert]

Sounds like a testing problem in the result getting 325 ppm. Or maybe you did not wait for it to mix in enough.

There is no hiding place for calcium when it is added.