Calcium and Top-off

[andysgr]

I have an RO/DI unit that goes into a tub that then works as a top-off system. Thus far I have not added anything to this top-off water. I have to add calcium frequently and I am thinking of addind calcium to the top-off water. Good idea? Should I set the top off water at a certain calcium level? What level? Thanks.

[kau_cinta_ku]

[welcome]
I wouldn't add your cal. to your top off IMO

[bertoni]

This article covers calcium and alkalinity dosing techniques:

http://www.advancedaquarist.com/issues/feb2003/chem.htm

Adding calcium to the top-off water can work, but alkalinity is more critical, usually, and both can be hard to control if used as topoff. Limewater usually works better for that purpose.