How Many GPH?

[FishDad2]

My LFS guy built my new tank with a circulation pump that's way too powerful...Gen-X 70, which moves more than 1,500 gph. The problem is that the massive volume of water returning from the tank generates micro bubbles in the sump...more than baffles and filter socks and all the other solutions that have been suggested can cope with. Short of closing a ball valve to cut back on the flow, there's little that can be done at this point to modify the sump and remedy the bubble issue.

So, the question I have is, what gph (or tank volume tunrover rate) should I be shooting for on my 225 gallon reef tank.

Keep in mind that I have a pair of Tunze 6000's inside the tank for circulation, as well as a closed-loop spraybar moving water under and behind the rocks which uses a Gen-X 40. Together, the Tunze Streams and the Gen-X 40 have combined gph ratings of almost 4,900 gph...so I'm getting a fair amount of water movement already. The recommendation I'm looking for is just for circulating water through the sump where it will feed the skimmer and refugium.

I intend to replace the Gen-X 70, as I don't see the point in paying to power a 300 watt, 3.2 amp pump if I'm just going to turn around and squeeze off the flow. Seems to me to make more sense to swap it for an appropriately sized pump which will almost certainly use considerably less electricity.

I'd like some recommendations so I know what to go to my LFS guy and push for. He made the bad decision at the start, he should fix it.

Thanks