protein skimmer putting out return bubbles


Reefing newb
I have a 55gal tank with a converted wet/dry filter. About two weeks ago I replaced the Bio balls with live rock and cheato. Today I bought a in the sump protein skimmer. I adjusted the side return tube so that the bubbles rise in the bubble chamber right to the bottom of the collection cup. My problem is that the bubbles are also being fed through the side return tube back into the sump where they are being pumped into the tank. The skimmer came with a foam sponge that goes around the side return tube which is supposed to stop the bubbles, but I'm still getting them. How can I stop them? The skimmer is a ASM MINI-G in the sump protein skimmer.
It can take a few weeks for a new skimmer to break in. It might quit shooting bubbles in a few days. You will just have to do your adjusting to get a balance that works for you.
If you're still getting micro bubbles after the skimmer breaks in, you can try adding pvc piping to the skimmer output area to make the output longer (from what I've read, the longer and more winding the path the water has to travel from the output area to the sump, the fewer bubbles you will have). You can also try hanging a sock filter over the skimmer output to reduce bubbles. I had an issue with microbubbles (and wasn't able to add baffles into the sump to trap the bubbles), so have resorted to pvc piping and a sock filter and it works great. Just make sure to rinse the sock filter once a week.

If you are talking about big bubbles and not just microbubbles, then you might want to dial the skimmer down. I have mine set so that the bubbles start forming about mid-neck, below the skimmer cup, and this allows a nice head of foam to develop and travel up the rest of the neck into the cup.
Skimmers just take a while to break in. I run my skimmer for a few days with no bubbles just water. Then turned the air on and within a few days I dont have micro bubbles.