I would call.... I've always had good experiences with AE Tech, though I call them not email them. Gary has always provided good recommendations about tuning etc. Also, I've noticed using a Mag 7 with the RD, depending on what the actual throughput is, you may want to put some tubing on the air intake of the skimmer and connect with a gate valve. In one of my systems that uses the RD, I have the Mag 7 in the sump and there's maybe 2' of hose, but I need to throttle back the air intake or it way overskims. In addition, if you can see any water in your riser tube, your gate valve is closed too much, open it a little. How many bioballs are you running?