Fluval 405 and Micro Bubbles

[Douden996]

Been running a Fluval 405 on my 30 Gal tank, and its a little over a year old, and started getting to where it spits out a large burst of micro bubbles every 5 minutes or so. All connections seem tight, and no leaks anywhere. Its not the usual case where air gets trapped during filtration changes where you rock it front/back, and side to side to get the bubbles out. It has to be pulling air in some place, and my thoughts are maybe around the small manual pump/valve on top where you prime the unit for start up. I think this part is replaceable, but the one thats on there doesnt seem to be bad/cracked or anything. Any suggestions?

 

[fishgate]

Are you using the filter sponges and filtration pads? They clog very quickly and once clogged spit out micro-bubbles. My advice it to remove all of the sponges and pads.

 

[biodegraded]

Maybe it's something chemical or biological generating gas rather than a leak to atmosphere.