bubbles in j tube

[mikev]

i have a tidepool overflow rated at 600ghp. it has been in constant use for years, but here lately i have been getting large air bubbles in the j tube. im constantly having to "siphon" them out. is this a sign of a weak pump or is there another problem?

 

[dogstar]

YEP....IMO its a sign of weak flow thru the tube,,flow must be strong enough to pull bubbles on thru the tube..if this systems been up for a while without problems and now your getting bubbles then its a good sign the pump is getting weaker and produceing less flow.