So I'm about to set up my Aqua Medic ATO unit and have a 10g glass tank for R/O Water. Should I anticipate any problems mixing Kalwasser into the top off water or any other issues that might come up. Bear with me through all the ????. I've never had a reef tank before said:
Kalk in top-off is not a really good methodology, primarily because you want to drip kalk in regular quantities that your tank can handle. Top off will vary based on temp, humidity etc. Also if your ATO fails and dumps water in, you end up with a big spike in pH.
That said, plenty of folks do it but I never recommend it. I am a firm believer in dripping kalk in a user interactive fashion. Get yourself a drip bottle with an IV line and a pinch clamp and do it that way.