I don't have any great pictures so I stole one from my build thread on TCMAS but the kalk mods have been extremely successful and I use a double ATO switch from @AVAST Marine as well as a pair of @SpectraPureInc pumps pulling from my freshwater reservoir. One pulls in RO bypassing the kalk if the sump level is below the lowest switch while the kalk runs anytime the pH is below 8.35 and below the second (higher ATO Avast switch). The Avast pressure switch is easily the safest ATO switch I've used in 20yrs... simply nothing to fail other than not securing the hose to the switch.
As long as I keep the evap up then it runs like a dream. Drops show a time where I turned off the kalk.