Refugiums

Question
Why does the water in my return compartment of my refugium  goes up or down with out me making any changes in the water contents of my aquarium I had the water in my return compartment set at 8 inches some days it rises to about  10 inches and there are times when it drops down to about 7 inches I understand that could be to evapuration
but why does it go up?

Answer
Hi Stanely. The water level going down in your refugium is more than likely due to evaporation. Why it goes up may be due to a small clog somewhere in your return outlet to your tank. It also can be from any clogged filter media or sponges.(I don't know your set up so I couldn't tell you exactly where the clog could be) For some reason the water is not flowing back into the tank as fast as it is going into the refugium causing a slight back up. It happens sometimes when something is clogging the return. Suddenly whatever may have been causing the back up dislodges and the water level returns to normal. Always make sure to keep the return lines free of any debris or creatures. I once had a large snail blocking part of my return and if I hadn't caught it in time he may have caused my sump to overflow!