precipitation?

Glenng78 · Mar 24, 2020

So I've been having issues where my tank was consuming more alkalinity than i thought normal, since i got my trident and I've been getting several daily readings. Anyway, I did a big water change today, and i noticed my sand is very hard and clumpy, so i am assuming i am getting precipitation. Can any of the wizards here explain to me what exactly precipitation is, how to know if you have it, and how to mitigate it? Btw i use fritz salt, and i mix it in a 36 gal brute can, and i have noticed some crud in that can as well. my levels right now after water change look like this.
ALK- 8.09
CA - 434
Mag - 1366
Salt- 35.4
PH- 8.06

Randy Holmes-Farley · Mar 24, 2020

Precipitation is formation of calcium carbonate. It always happens to some degree, especially in new sand because the sand surfaces act as seed crystals for precipitation.

To reduce it, use low pH alk additives and otherwise keep pH on the low side, keep alk low (7 dKH), keep magnesium high, organics and phosphate not too low, and calcium not too high.

Glenng78 · Mar 24, 2020

How do I avoid it in my mixing station ?

Randy Holmes-Farley · Apr 6, 2020

In a mixing station, your options are limited, but dose nothing into the new salt water, don't heat it. Aerate it initially. Mix fast, then stop mixing.

or ignore it. I ignored it and let a lot of solids build up.