Micro bubble question

[njhadfield]

I have been in the hobby for about 4 years now, and I have a 90 gallon reef tank and have been dealing with micro bubbles ever since. I have a 40 gallon sump just belowe the tank and always thaught it was my protien skimmer putting micro bubbles back in the the sump. I made my own sump and put in 4 baffles to help with the bubbles but that did not work. I have a pse 1000 protien skimmer which I know is not the best but it works. I just put a 90 degree attachment on the output of the skimmer and now the water flows into a 4 inch 200 micron sock to help stop the bubbles. I also have a 7 inch sock as well for the return from my tank to the sump. I have tried to prevent the micro bubbles returning to my tank as much as possible. What am I doing wrong? The only thing left would be my return pump which is a mag 1200 pump going verticle staight into my tank with only 1 90 degee arm. Could there be somthing going on between the pump, ball valve and the 2 arms that disperce water back into my tank. I currently see no mico bubbles in the sump, only in tank. I even dummed the flow down to about 200 gallons per hour in to the tank hopping to stop the breakup of the bubbles.

[TheFishMan65]

How far is the last drop over the last baffle? If it is too big it could be producing bubbles.

If there is a pinhole lean in the return plumbing the water flow could suck in air and create micro bubbles. Assuming it is PVC can you paint another lay of solvent on?

[coralnut99]

Do you have enough room in the return chamber of the sump to face the inlet of the Mag12 a full 180 degrees from the last baffle without it being too close to the sidewall of the sump? If there are microbubbles being produced after the last baffle, at 200GPH they shouldn't be getting past the last baffle with much turbulence/velocity. This may give whatever bubbles get into the return pump chamber some more time to just get to the surface.

You may also want to take a look at the water level in that chamber as well. The pump inlet may be creating a small vortex at the water's surface. My Mag12 draws surface air when there's less than 2 inches of water above the pump's inlet.

I have one other thought that would be tough to describe, but maybe the above will help.

[Steveb]

You might try threading on a 1.5" x ¾" SPIGOT X FIPT Reducing Bushing and then slide a 1.5" slip 90 degree elbow on facing down forcing the pump to draw water off of the very bottom of the sump. I do this with a Mag 5 and a Mag 3 (bushing is smaller and elbow is 1").