Air valve for durso standpipe?

[Gatorfreak]

I have a durso standpipe in the overflow of my 90g. It's been going ok for over 2 years now but I'm always having to adjust how much air it needs let into it. It'll be fine for a few weeks and then the water level in the overflow will starting going up and down and making gurgling noises. Does anyone else have this problem?

I was thinking if there was some kind of air valve that I could use that would let in air based on how much it's sucking it in. Maybe something with a rubber flap that has to be sucked open. Just a thought.

I can't be the only one with this issue... can I?

[melosu58]

Moved to Hardware and equipment discussion.