tom's reactor is a great design, i've made two of them, top and side mount and both really work. why they work is beyond me . it seems that saturation is much better and faster. i think the side mount is easier to build and looks better. viewtainer 2.00,pump 11.00, toilet supply tubing 3.00 and your set to go . anyone interested in just how i do it get ahold of greg watson, he will give you my phone #,i think. regards,cornhusker