Let me know if the Float valve crusts up and sticks.. thats only thing i see that may be an issue.
great job.. I find my Kalk vessel stays saturated once mixed for months. I make a 2 month batch of 50 gallons at a time and it is drawn off by a Doser pump at a set amount per day. from the bottom of the vat, which fills/matches my evaporation rate closely. Also watch for back siphoning where it enters the Tank area. With he check value that should be ok though.