Sump Microbubbles

[redwinger]

I am having some serious microbubble trouble. I have attached a drawing of the design I am using. This is a 20 gallon high sump. I have a 75 gallon reef ready AGA with the megaflow kit. I am using a mag 9.5 for a return pump that is on a ball valve to adjust flow if needed. I installed the baffles to help with this problem but they are still getting to the display tank. The baffles are about a inch apart and one inch off the glass on the middle baffle. The drain line is about two inches below the water line in the sump. This is where the bubles are coming from. They are not coming from the skimmer, or the return pump. If I turn the pump all the way down to 1/4 open the bubbles subside. If I open it all the way up to get the desired flow I want the tank is full of bubbles. What should I do?

[RobinsonFam1]

sounds like your bubbles are coming from the overflow in the tank or a pinhole air leak in the plumbing. what is removing the water from the tank to the sump? can you see if the air/water is mixing and going in there? yyou might want to add another baffle also.
HTh
BR

[akula]

I also have a 75G and a mag9.5 return pump. for me I just run the sump water level high, almost at the top of the highest bubble trap plate. when the water level gets low enough, some bubbles get produced as the water cascades over the last bubble trap plate and given the strong pump, any bubble in the pump area will get sucked into the pump and chopped up. as long as I have the water level up high, there are no bubbles formed and or they are to far above the pump inlet to be sucked in. changing the water level is an easy thing to try. my pump is wide open. might try turning the pump inlet away from the baffle plates. that way it is just a bit harder for bubbles to enter the pump.

[Lutrah]

Perhapps a fourth baffle for the bubbles to pass under before they are pumped back to the tank.