getting more Ca into solution in limewater


Premium Member
No, not using vinegar. I've been through all that discussion already.

But a friend of mine has asked if he can just add Ca salt, like Ca chloride into the RO reservoir that gets pumped into his Kalk reactor in order to get more ca into his tank without dosing by hand. I'm pretty sure this wont work. Something is going to precipitate, right? I'd like a litte more explanation though.

Randy Holmes-Farley

Reef Chemist
Premium Member
You are right that you cannot do it. It will cause less lime to dissolve into the water, resulting in less alkalinity in the delivered limewater. If you need to make occasional corrections to calcium or alkalinity, add them separately of the limewater.
The solubility of the lime (calcium hydroxide) is limited by the concentrations of both the calcium and hydroxide ion in solution. Boosting the calcium artificially will drop the amount of hydroxide that is compatible with it.