Have you tried the
soda curl solution?
Is it the intake, or the output that's messing about with your betta?
Before I gave in and bought a new filter, I put a big, fat, piece of bogwood at my filter's intake (it was an Internal filter, so the intake was long and flat, not a tube like most 'hang on back' style filters), and followed the DIY to kill the output.
Eventually, I did give up and just get a new filter. I studied up and looked around and finally... realized that no matter what I did, it was simplier to get a new filter. I just took my old sponge and crammed it into my new filter. It didn't fit beautifully, but my tank didn't go through a minicycle, either.
*Oh, I should note, that Pepsi brand plastic bottles are built better than Coca-Cola brand plastic bottles, for this service. They're about 1/2 an inch longer, and that makes a difference in the diffusion it creates. If you're a Coke drinker, like me, suck it in and buy a Pepsi bottle, give it to someone else to drink if you have to.
I generally loathe Pepsi, but I bought some Mountain Dew, and it was fine. It's a bit of an eyesore, but if you're unwilling or unable to get a gentle filter, it'll do in a pinch.
/www.theaquariumshop.co.uk/aqua-glas...arium-o-36.html
