I liked the bubble filter idea so much i had to try it out. I drilled a hole in the intake basket on my closed loop and stuck a black ro/di line in it with a cut off valve. worked great! I need to find out why the bottom right isn't doing it so well (could be the rocks) and hook up my lock line flat heads. But it seems to be a great idea. I'll keep in mind Mikes, (mojo) advice on not doing it to often. Great thread!