Is it normal to have the ALK level drop by .9 dKH per day?
I have a 72gal + 20gal sump (3/4 filled with water). I have a mix of different type of coral (SPS, LPS, Soft). Evaporation wise I lose about 1 gal per day, but it gets refilled with an ATO. What uses up the ALK? Is it the corals?
I am dosing BRS 2 part formula. I was just wondering if the cosumption seem excessive.