Posted: Sat Sep 10, 2011 4:40 pm Re: cascade canister filters
The fx5 is 21 inches high (that may include the hose connections, yep, just checked, the lid is 16.5 inches), and the lid must be at least 7.8inches below your water level.
As far as the purigen goes, I haven't replaced mine yet, but according to the manufacturer, 1L will treat 1000 gallons up to 6 months, I use a 100ml bag, so with my 3/4 full 75 gal tank, should be good up to a year with the carbon, we'll see. It also says that using it with carbon will extend its life, you can tell when it is exhausted when it turns dark brown (fresh it is white). It can be replenished by soaking overnight in bleach, and then soaking in a dechlorinator solution. I think most people get 2 100ml bags so they can just swap bags and regenerate the used one.
5 inch RES male named Jordtim
Hardware: 75 gallon tank (21"H X 48"W X 18"D), FX5 filter with veipacray media setup, pool filter sand substrat, TurtleSafe halogen heat/UVA lamp and ReptiGlo 5.0 UVB lamp in ZooMed Dual Dome Fixture.