Hello, guys. I bought a new hob 1.5 on Friday from marine depot for my IM 25 lagoon. The skimmer is pretty nice. When I first install it, it starts making bubble right away. The original return tube. It's not long enough. So I changed it to a longer white PVC pipe. However, the return hole in the skimmer body is sucking air. It seems like the water level in there is a tiny bit low. I can't find any way to increase the water level there. Or is the sucking power from the return line is too strong Do you guys know how to fix this? Thanks in advance.