Ca tested over 500ppm

[BradB]

I try to test Alk at least weekly, but even there sometimes get lazy. Ca rarely gets tested, as I mix and does equal parts of 2 solutions that should keep the two balanced.

I was shocked a week ago when I tested Ca (via Salifert) where titrating with 1ml of "Solution C" is supposed to be 500ppm and had to titrate around 0.2ml more to get the color change. I lowered (but didn't stop) my Ca dosing by half, and a week later, I am near the full color change with the full 1ml titration, so my Ca tests around 500ppm. Usually when I hit the end color, I add a drop or two more just to be certain there is no further change, I didn't do that this time.

This is not a brand new test kit. So while I know (or at least believe) it was originally accurate, I wonder if it could have expired and my "Solution C" is not as high as it used to be.

How likely is it my test kit is the problem and not my Ca? Other than buying a new kit or waiting for an ICP, is there any way to check? If Ca is my problem, should I stop dosing completely or keep dosing around half?

 

[Randy Holmes-Farley Verified Community Expert]

I try to test Alk at least weekly, but even there sometimes get lazy. Ca rarely gets tested, as I mix and does equal parts of 2 solutions that should keep the two balanced.

I was shocked a week ago when I tested Ca (via Salifert) where titrating with 1ml of "Solution C" is supposed to be 500ppm and had to titrate around 0.2ml more to get the color change. I lowered (but didn't stop) my Ca dosing by half, and a week later, I am near the full color change with the full 1ml titration, so my Ca tests around 500ppm. Usually when I hit the end color, I add a drop or two more just to be certain there is no further change, I didn't do that this time.

This is not a brand new test kit. So while I know (or at least believe) it was originally accurate, I wonder if it could have expired and my "Solution C" is not as high as it used to be.

How likely is it my test kit is the problem and not my Ca? Other than buying a new kit or waiting for an ICP, is there any way to check? If Ca is my problem, should I stop dosing completely or keep dosing around half?

500 ppm calcium is fine. I currently recommend 400-550 ppm calcium. :)

 

[mtraylor]

Check the date on the salifer test kit and ensure its not too old. Get another test kit or take to LFS to see if it matches. CA at 500 is no big deal. Some salts mix at 500. You can stop dosing for a week or get more coral and the issue will resolve itself. Cut your dosing down some for your current bioload and it should be fine.