Here's my custom 5-gallon "Reef Crystals" brand kalk reactor with patented carrying handle ;D It goes inline between the R/O unit and the float switch. I'm hoping to get this sealed and pressure tested early next week. The whole thing cost me around $25 including a small pump on a timer to stir the kalk every few days. I fully expect this thing to either leak like a sieve or just blow up and flood my basement :
