I'm running both RKL's and ACjr's. The RKL is easier to program than the ACjr. I have had trouble with both, RKL customer service was "meh", they wouldn't respond until I posted on one of the big boards that I was having trouble and couldn't get anyone to answer me, the service for the ACjr was non-existent (as in, "leave us alone, we have your money, not going to help"). Not terribly impressed with either one, but if I had to make a choice I would go with the ReefKeeper, just because it is easier to program, and they do eventually return your emails/phone calls.
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