Steve, Thanks, there was a large amount of tiny carbon free floating in the canister(so much for Marineland's claim at evenly sized carbon). I cleared them out and switched to the tri-based pellitized carbon I bought from memory doctor (identical size pellets).
I think I figured out where most of the air was/is coming from, air stuck in the "u" elbow and that the tube on the intake connected to the quick release valve was not truly seated right (as it wasn't an even cut). So I fixed that as best I could. I believe that since the canister is not on ground level there's not enough pressure to properly burp the the canister so air is sitting in the "u" elbow of the intake. I got most of it out doing repeat burps and completely submerging the intake stem, relocking the valve, and keeping the other end submerged as I reattached that half of the quick release intake valve to the canister.
This reduced much of the bubbles that were visible, coming in from trapped air in the elbow. Now I suppose I need to (with the unit off...) pull water through it backwards (w/ PH
) to completely expell all the air.
Just when I thought I was reducing head pressure and maxing my GPH
by elevating the canister 2 feet off the ground it backfired by keeping back syphon pressure (I think ???) low so that the unit will not completely burp.