Question about lime (calcium hydroxide)

[goldrimtang]

I just started adding calcium hydroxide to my freshwater top-off tank. I added 2 tsp a couple of weeks ago. My display tank is 150 gal.

Things look good, calcium is at 450 and Alk 8.5.

Now in the fall, the tank evaporates about 5 gal a week. Should I add 2 tsp every week, as I fill up the fresh water tank with RO water? or should I wait for the calcium / Alk to drop before getting more Ca(OH)₂?

Thank you!

 

[jay.fishman]

How much kalk sediment is left in your top-off tank after a week? Use that as a guide for when to add more. Realize some of the sediment is still usable kalk and some will be precipitate. Consistency is a good thing.