I drip Kalk directly into my tank, but only at night after the lights have been off for a couple of hours. At first I was one of those who tried the 24/7 drip, but the Ph was too high during the daylight hours.
Since my evaporation rate has decreased, I find a 2 1/2 gallon container of Kalk lasts about 4 days at my evap rate, dripping only till lights on in the a.m., this for my 40 gal/reef.
My humble .02
HTH
Hermit