I suppose if you make sure you're not dosing more kalk than you evaporate from the system you're fine. You know, I'm just thinking, in my climate especially, it can vary quite a bit between summer and winter, but maybe in your case less of a difference.I had an idea how much I evaporated as I know how long my ato container last. I did check for the first day or two to make sure I wasn't flooding my sump.
I am sure evaporation changes throughout the year but I don't dose kalk through my ato, so no matter what I dose the same amount of kalk each day. My ato still turns on, so even is evaporation slows I won't flood anything.
I've used kalk in my ATO off and on in the past but don't currently use it. I might have to look into it as my tank and sps get rocking...I mean after all, kalk is the tears of the gods I hear...