slakker - very good point on the ATO units. I've had a few close calls also with mine, but thank goodness I had the secondary emergency float set low enough that it stopped an overflow. My blue linkia star has also caused problems by blocking flow through the gate and dropping the level in the back. Right now I'm running the ATO on manual till I get a fuge in and remove everything in the back. It's still a lot easier to plug the wire into the Osmolator control box than hauling water to the tank.