I have been having problems with this on an intermittent basis. Sometimes the pump will over fill the tanks and other times it will not add any water. There was a period when the only way to get the system to work was to unplug the unit. It would then fill the tank one time and not work again. Lately, it has been working. This morning I woke to the tank being way over filled. There is no pattern it is random. I am unhappy as this is for a thirty gallon reef and I am seeing a significant fluctuation in salinity. The osmolator is only four months old. I bought this system to keep my tank at a constant level. It is not working. Any help would be greatly appreciated. My phone number is 8137605293. Thanks.