I had a reefkeeper II with the expansion plug and ph probe a couple years back with my old 125 and I liked it. I had a problem in the controller, sent it back, they repaired it under warranty, and everything worked fine. This is an older unit not like the high tech integration and internet connectivity that is available now but was nice to be able to control everything with the cabinet doors closed. It really helped me relax when leaving the house for a couple days. The biggest problem was keeping the ph probe calibrated. The readings were only as good as the accuracy of the measuring device.