Coralife 65 producing large bubbles from output

[Deathstrudel]

First off, I have a 36 gal bowfront with 50 lbs live rock, polyp and lps corals, a gobie and a blenny, and an appropriate sized cleanup crew. My levels are 9.0 dkh, .02 nitrate, .04 phosphate, and a ph of 8.5. My tank has been up and healthy for about eight months, and Ive been using a coralife 65 skimmer since the beginning. Its worked great up until about a week ago. Now ive got large bubbles coming from the return, with loud annoying noises with it. I have had to add some extra seaweed for the starving emerald crabs, but not much, and other than that there have been no changes to my setup.

So... how can i stop this annoying development? The bubble trap hasnt changed placement or composition either, and since i have no sump, i have to use it as a HOB. Any advice would be greatly appreciated!

 

[Joeganja]

Clean the impeller.