Which model Fluval was it...

[Slinky_Bass]

that lost it's air tight seal thing when switched off for maintenance?

[f1oored]

I've read about people having leaking problems with the 404 but it doesn't sound like that is what you are talking about.

[Fishguy2727]

I use 03, 04, and 05 models and I have not noticed that in any of them.

[cocoa_pleco]

I use 03, 04, and 05 models and I have not noticed that in any of them.

me either.

[*Sarah*]

I think ours is an 305, and no problems, but its pretty new still.