[ChuckG]

Originally Posted by DaveK

A kalk reactor should be sealed to keep air out, since air will cause the kalk water produced to be much less effective. In other words, hold a less calcium. This is also why you should mix kalk water daily, if not using a reactor.

Inside a kalk reactor, some method is used to keep the kalk in the lower half of the reactor constantly mixing, Often this is done using a small powerhead, but other stirring methods can be used. This mixing is just enough to keep the lower half of the reactor looking cloudy, and the top part clear.

RO/DI water goes into the reactor at the base, so it mixes with the water containing all the suspended kalk. Sometimes this is done via a tube that runs inside the reactor and comes out the top of the unit. The output kalk water is drawn from the top of the reactor, from the clear water.

Interesting. I would think that a power head would move ALL the water inside a reactor. Guess I'll just have to try it and see.

Originally Posted by Tangboy

Sweet, that sounds like an interesting plan that you have already figured out how to back up for those "oops" moments. I know right now as I plan to set up the schools 70g tank as a Predator tank I'm trying to figure out an easy AT system. Any experience with those for a reasonable price also without taking up much room under the tank?

A cheap ATO? Sure - A 5 gal bucket, a couple of connections and a float valve. Probably about $35.