Be cautious when/if using a float valve to release Kalk via ATO. A friend was using one model valve where the Kalk(Top off)) actually went through the float valve itself. Over time the Kalk built up on the float valve, it stayed open and pumped 30g of Kalk into the system; lost $20K worth of live stock
I use a gravity fed system i.e. drip, for Kalk only and a Tunze Osmolator for ATO.