I'm currently using the same skimmer and used the 65 before but only as a hang on. I'm going to a Marine Tech HSA-250 that doesn't help you but this might. As per the instructions put the skimmer on a stand so the pump is approx 3 inches below water level and adjust the red knob as it says, this skimmer can work okay but is extremely sensitive to water level changes ( as a lot of skimmers are apparently) so an ATO is pretty much essential, I found I had much more success once I added the ATO. Try to make sure your water level in the skimmer neck is just above the red collection cup threaded ring. Which should give you a pretty dry skimmate. Hope this helps. I'm planning on a fairly heavy bio load hence my reason for going overkill on a rated 250gal skimmer in my 72 gal bow
