I belive tank is precipitating Calcium Carbonate. How do I stop it?

[Luengineer]

I have a new 60G tank (6months) with refugium (20g) and about 12 LPS frags /small colonies.

I have been adding Kalk via ATO; 1 TSP/Gallon. About 1.5 Gallon/day.

Parameters
Ph 8.1 - 8.3
Ca 450
Mg 1400
Alk, currently 7.1. However, had dropped from 9.1 to 7.1 in 36 hours despite above kalk dosing. If I stop adding Kalk, it will drop to mid 5s in a few days.

I believe I'm seeing precipitate on sump wall.

Thoughts?
What should I do here?

 

[Righteous]

High pH and high calcium can increase precipitation. Have you double checked your numbers with other test kits?

 

[Randy Holmes-Farley]

Switch to a low pH alk additive, at least for w while. Like baking soda. Add alk additives slowly and dilute well before adding. Do not drive phosphate and organics too low. Make sure magnesium is adequate to high.

 

[BeejReef]

Had this happen twice when trying to get kalk dosing dialed in.
This vid solved it for me.

FAQ #38 I add Calcium and Alkalinity Solutions but the levels are actually dropping?

Today on BRStv, we have another episode of BRS 52 FAQ where we answer all of your frequently asked reefing questions from our popular 52 Weeks of Reefing series. Today we're answering Lisa A’s question “I keep adding more and more calcium and alkalinity and the levels just won’t rise?" It can...

www.bulkreefsupply.com

I'm sure the above suggestions are spot on. Essentially, I had to just stop dosing kalk for an uncomfortable amount of time, clean any precip I could find, and start over with a smaller dose with a slow ramp up. The vid says to stop dosing for a day. I had to stop dosing for three... something about the existing precipitation becomes inert and stops sucking as much of the new dose out of the water.