Another CA test gone bad

[Redbarnreefer]

I've read about others experiencing this but didn't give it much thought as I go through my tests well before their expiration date. My "old" -- less than 1 yr -- was off by 170 ppm. It was giving me a reading of 400 when I was really closer to 570.

That got me to thinking, how many have experienced this. Have you noticed it on one brand more than another? If there is a specific brand that has a problem with this it would be nice to know.

 

[Randy Holmes-Farley]

How do you know it was off?

 

[Redbarnreefer]

I bought a new test kit and when I got such a high result I brought a water sample to my LFS to double check it. I did a 25% water change last night and this morning CA is reading around 500. @Randy Holmes-Farley would having such high CA affect my alk? I top off with Kalk water and dose 2 part once a week as needed. I didn't really notice an increase in alk dosing though...

 

[Randy Holmes-Farley]

High calcium isn't a problem, unless it is super high (well over 600 ppm). Doubling the calcium from 400 to 800 ppm will only have about the same effect of calcium carbonate precipitation as boosting the pH from 7.9 to 8.2.

 

[Redbarnreefer]

Would this be true in a low nutrient tank as well? As I understand it high alk in a low nutrient system can cause burnt tips. Could that be true for cal?

 

[Randy Holmes-Farley]

No, not true for calcium since it does not control the rate of calcification,.