[wetcoast]

I've took the plunge and put together a sump in my 65gallon system about 3 months ago and all has been working without issue. I purchased a black acrylic Overflow box (some people call it the weir overflow) and a line connected to the SEIO 820 for suction. This drained into the sump.

Tonite I noticed my water level was very high so I turned off the power to the return and powerhead and turned things back on - this time nothing was draining into the sump!

I took the hose from the box off and tested for suction pressure - still there - then proceed to take the box off the tank to inspect for any clogged pieces.. I didn't have that thin of a brush so I couldn't do a thorough clean inside of it - but have tested that water can travel all the way through by filling one side and tipping upside down to have it travel the path.

I have even gone to putting the overflow on backwards at the front of my tank with no hose connected at the drain just because I'm sure it's not going to start the siphon.

I'm starting to panic a bit here - have moved a heater into the display - and need to fish out an urchin from my refugium for the next little bit until I can sort this out. Can anyone provide any advice as to what I can do?

Completely Baffled!