Air in overflow tube, please help!

[sduda]

I have an overflow tube on my tank feeding my sump. I have had the tank setup for over a year now and all has been well. I recently have started having problems with air getting into my overflow tube and causing the siphon to slow down which starves my sump and thus causes air bubbles as a result when my pump cavitates because of the waterflow slow down. Does anyone have any suggestions please?

 

[jakepilot]

Of all the problems to get, this is actually pretty to fix. give the siphon tube a good shake and the air should pull through the tube...the recent air in your tube could be attributed to a leak in on of your tubes..the siphon should be stong enough to pull the bubbles through the tube in the unlikely event they get trapped there. can you watch and see how the air is getting in there? is the water level in the tank a bit off, to where the overflow box is low or something

 

[sduda]

Just when you thought you were doing something smart... I was cleaning the pump to ensure that it was not under performing, (it is a CAP2200), and I was brushing it off under luke warm water, pulled the impeller out, stuck my finger in where the impeller goes only to break that darn shaft off 1/2 way down! It seems to be functioning so far but it is just my luck... Any suggestions of a pump that I may want to consider replacing this one with?