[fkshiu]

Originally Posted by Black Phantom

Here's a good product thats quite cheap. I've run one on my 50 cube and it works not bad. Not anything like a Tunze system but a heck of a lot more affordable.

http://www.jlaquatics.com/product/wm...+Director.html

I had one of those things briefly. Worked well for the price, but it would gum up pretty quickly and it cut down on head pressure by quite a bit so you'd need a pretty big pump for a tank of the OP's size. The only way you can control the switching action is with the pump itself: the more pressure, the faster the switching.