Water Flow Oddity

Looking for some advice. Just entered the saltwater reef world about 3 weeks ago. I have a 72G bow front that is not pre-drilled. Everything has been working fine since I set it up. Today I spent about 15 minutes moving some things around and had my arm in the tank the whole time. After I was finished, the hang on overflow box started acting funny. Every 30 seconds or so the outside box runs down a little and then refills above the drain line and causes a small surge of water down the tube. Have tried everything to get things back in sync and just cant figure it out. Any ideas?

 

Do you have an air inlet that is getting covered up somehow? That "flushing" behavior is common in drains that don't have a way to get air into the drain line.
You could look up Durso standpipes or Hofer Gurgle Busters or some other type of noise reduction device for ways to deal with it if this is the case.

 

Thanks for the suggestion. I think Im showing my rookie status on this one. Checked with my lfs and he said air in the line. Told him the j-tube was fine and he said no, check the line running down to the sump so I jiggled it and problem solved. Good think Im not a plumber...

 

ya i noticed that with my eshopps overflow. if i put my arm in my tank(displacing water and causing a small sudden rise) my overflow makes a chocking noise for a little bit but it clears.