Calcium Level Fluctuations

smd189 · Jan 24, 2021

Good morning. I have been using Seachem Reef Advantage Calcium powder twice a week at 10g in my 65 gallon (actual volume). At dosing, levels hit 410ppm. With daily testing I have found that levels drop by 5ppm per day. It states to dose twice a week and I have been doing it on Monday’s and Fridays as I travel in between. Based on this, my calcium levels go from 410 on Monday to 390 Friday before the next dose.
What are suggestions here? Is this okay? Should I increase the dose so that the levels stay higher across the week? Are the 20 ppm decreases across the week harmful?
Right now I have CUC, fish, and soft corals. No SPS or LPS. Thank you.
Shawn

Randy Holmes-Farley · Jan 24, 2021

Calcium is not generally a limiting factor for anything as long as there is enough. If you are in the 400-550 ppm range, the exact value doesn't likely matter.

I'd boost it from where you are now so that the mid point of the experienced values is around 420 ppm, then dose a few times a week to keep it there. The twice a week guidance is not really sensible. Some folks need to dose much more often, and some could dose less.

smd189 · Jan 25, 2021

Thank you very much. Is there any harm that comes from dosing the value from 420 to say 440 all at once and then having it drop over a few days back to 420 and so on. Basically, can the swings hurt my fish? Thanks again.

Randy Holmes-Farley · Jan 25, 2021

smd189 said:
Thank you very much. Is there any harm that comes from dosing the value from 420 to say 440 all at once and then having it drop over a few days back to 420 and so on. Basically, can the swings hurt my fish? Thanks again.

That is fine.