I'd try placing a piece of sponge over the intake tube...this should help reduce the flow...I have a bunch of AC 20's for sale $10 ea and I'm pretty sure I may be heading out to lang this weekend...let me know if your interested...
I found this may help http://www.guppies.com/forums/showthread.php/top-fin-10-19155.html?
Dean
I found this may help http://www.guppies.com/forums/showthread.php/top-fin-10-19155.html?
Dean