Thanks Marc. 
Good point on the valves, I'll open them up a bit more and see how it goes.
The fuge has no sand but there was a huge detritus buildup there. I just need to be more vigilant about cleaning it once a month.
The microbubbles has me stumped. I believe I'm getting bubbles from both lines (return and CL). I've redone the connections on the pumps and literally poured glue over all joints yet I still get them.

Good point on the valves, I'll open them up a bit more and see how it goes.
The fuge has no sand but there was a huge detritus buildup there. I just need to be more vigilant about cleaning it once a month.
The microbubbles has me stumped. I believe I'm getting bubbles from both lines (return and CL). I've redone the connections on the pumps and literally poured glue over all joints yet I still get them.