I use both on different system, and I am partial to the kalk reactor for simple use. I never have to refill the bubble chamber or change any bottles on the kalk reactor, or make any adjustments after doing so. My corner tank is full of LPS, SPS, clams, and other calcium users, but the calcium is consistantly in the low 500's. Last time I tested it read like this. PH-8.4, Alk-11.4, Calcium-545, iodine-6, phosphate- undetect, nitrate-undetectable. I run 75 gallons with 25 gallon refugium, 3.5 inch sand bed, and a kalk drip. RO/DI on a kent float valve for top off.
Tim Marvin
(512) 336-7258