Can you reduce hardness with calcium?

[ken6217]

Newbie here.
Can alkalinity be lowered by adding calcium? Is this a bad idea?
ken

 

[DrBDC]

Alkalinity will drop on it's own 1/2-3 dKh per day on most systems if you don't supplement any. How high are you talking about?

 

[BLockamon]

Adding too much calcium will cause the alk to precipitate as calcium carbonate. However, I don't recommend end. The resulting "snow" storm will probably irritate corals. Just let it come down on its own unless it's really high. If it's really high, do water changes.

 

[ken6217]

It was more of a theoretical question. I know there is kind of a inverse relationship between the two and was curious of you could reduce hardness by adding calcium, and also if this is a bad practice.

Thanks,
Ken

 

[Randy Holmes-Farley]

Yes, you can drive precipitation of calcium carbonate to reduce alkalinity and calcium. If you do that by adding calcium, then only alkalinity will decline, but unless you raise the ph as well, you'd probably need excessive calcium that would then be left too high.

 

[ken6217]

Thanks!

 

[Randy Holmes-Farley]

You're welcome.

Happy reefing.