This spa will be part of a new swimming pool, with the spa draining into the new pool. I will have two 8" drains, each with a 2" drain port, tying into a 3" line returning to the pump. The spa will have six return jets. In a "normal" setup, with "normal" pressure, how many gallons per minute (GPM) should I be looking at for average water pressure at the jet opening in the spa. If I'm pulling 70 GPM from each drain at around 1.7 feet per second (FPS) will this be adequate for the six spa jets returning the water to the spa? I could install larger drains so that I can pull more water, faster, but is that necessary? I'm planning on mounting the drains on the lower part of the wall of the spa and not on the floor, hence the lower GPM vs a higher GPM with a floor mount. My reasoning for the wall mounts is less likelihood of stubbed toes on the raised drain covers.

The other question regards introducing air into the return lines to the spa jets. Where and how do folks mount these systems, so that they are not obtrusive or invite dirt, sand or garbage into them from curious fingers and hands?

Thank you in advance!