+ As far as I know, hardness has NO effect on chlorine levels . . . or loss.

+ Trichlor will maintain chlorine levels just fine . . . IF you dissolve it. But undissolved trichlor has NO effect on chlorine levels. Also, I believe some 'diluted' trichlor tabs are now being sold.

+ Fully dissolving TWO complete tabs of 89% chlorine trichlor tabs is approximately equivalent to adding 1 gallon of 8% bleach, except that the tabs ALSO add CYA and acidity.