So I will admit that this is the first tank I've not had drilled. I'm using an HOB
overflow box and I've had it set up and working great for some time now. This past week I did my usual water change and then turned my equipment back on as usual. I always stick around to make sure everything is all good. About 5 minutes after start up I hear this bubbling in the sump. It then stops. Then a few minutes later it happens again and so on. It's air that is coming down the intake plumbing and into my skimmer area.
My question is: how do I make this stop? Why is it doing it now when it didnt before? Never had this issue.