Refugium Water Source

[intarsiabox]

I have a 50g tank with a 20g sump with refugium and would like to know if it is better to supply the refugium from one of the overflows or tee off from the return pump. I have a Mag 9.5 at the moment and had to throttle the discharge down about 50% to get rid of the micro bubbles. If I teed off from the pump could I increase the flow rate without getting bubbles or is the flow rate already sufficient? Thank-you!