My RedSea XL 300 has been up and running for 3 months (fully cycled) and is stocked with a fox face and a pair of clowns. I plugged in my protein skimmer today to start dealing with any excess nutrients but cannot stop the bubbles shooting straight up the chamber and overflowing into the cup. Have tried adjusting all valves and even raising the skimmer in the sump by 2 inches but no luck. Any help would be much appreciated.

