I just set up my sump, complete with bioballs. The sump replaced my canister filter, which was running for about 4 weeks. I plan to soon change over to live rock inside my sump, as early as this weekend. I also have a refugium, but I have not bought the light for it yet, nor have I placed any macro algae in it.

When I turned on my lights today, there wasn't any bubbles on the rocks. This is weird.

By the way, "Salt-P" I don't have enough flow. All I am depending on is 2 returns from my sump, which only has a 1200 gph pump that is "valved" down a little.

I have standard U-tubes (shaped like U's)... the bubbles subsided again (in tank) when the lights went off, and I noticed less in the skimmer when the lights are on, oppose to when the lights are off. getting ready to change to a sand bed, this weekend, anybody have any suggestions?

I have left a small tube in the U-tube that causes problems, so I can easily suck out any air build up. The tube is closed off between usage, so not to create a siphon. Might work for someone else who is having this issue.