Ok we are shutting down our 125 because of moving and not having room for it, plus our work schedules lately have preempted us from spending the time needed on the tanks. But after having one of these ecoaqualizers on it for a year and a half, and with our lack of upkeep at times, I would say that this thing works. We have not had a sick fish, and have had no real problems with the tank except for a xenia meltdown or 2. I firmly believe this thing works. I sold off a large portion of the rock today, got the water all cloudy and stirred up, but after refilling with water from our former qt to get the pumps running again and to keep whats left in there alive, I went back to the house about 4 hours later, and the water was crystal clear, and the fish were all happily swimming around looking for a handout. It may seem like a gimmick, but In my opinion, it does something that works. I will keep this device just in case we set up another tank in the future.