every thing is working ok,with the refugium/tank. murphy got me, but i did'nt let him hurt me. my 1/2 inch brass check valve is leaking a little, when power is out the water level went to max which is good, then kept rising very slowly after power was out it took overnight to reach the very top of my tank but i caught it in time before any water spilled. i took it apart and cleaned it, put back and no more leak. did the suckon the pvc thing to see if it worked then blew out and could not. before i cleaned it some air was leaking. i am confused about my cpr overflow, i took the entire pvc pipe out from the pump in refugium and the water level still rose. since the overflow has a tube attached from my 300gph powerhead to run it, is it possible this water is slowly getting sucked into the overflow and going down to the refugium? :? the water level is below the lip on overflow and the water still rose. i took the tubing off the overflow and heard that air sound for a sec. this has got to be what is going on. thanks for any feed back .walt