Overflow problems

[Drewlonius]

Hello all i have a question we set up a frineds tank he has a overflow box with a piece of PVC with a muffler on top and it keeps makeing a toilet bowl affect where the water rises then gets sucked down, the water rises about halfway up the muffler then down, we have a whole drilled on top of the muffler also and cant seem to figure out whats causeing this?

Thanks all

Drew

[Deano]

This is usually cause by back pressure in the overflow tube. If the exit of the over flow is below the sump water surface raise it above and see if it quits. If this fixes the problem. You can now start to lower the exit until you get the flushing effect again. Now you know the max depth the exit can be in the sump. Another trick would be to drill a couple holes above the sump water line in the exit hose. This will help to release the back pressure.