For nano AIO tanks IMO the only way to go is GFO and BRS Rox carbon in this reactor-> LINK
I used the CPE and Purigen for months. CPE does a very good job at making the water crystal clear (Rox carbon does this very well too). Purigen I believe does relatively nothing. I did substantial tests to determine if it was keeping nitrates down or actively lowering them and I found zero evidence of this. The GFO in the CPE does relatively nothing as well. The only way to really really lower phosphates with GFO is to run it actively where you can control contact time and have UPWARD
adjustable flow through the media. This pertains to carbon as well but to a much lesser extent. Downward flow with gravity through a media bag is a futile effort. Water will find the path of least resistance every single time. Media baskets help but physics will win out every time. This effect is limited substantially when water is pushed upwards through a reactor instead of flowing with gravity downwards.
Passively running GFO is like being in a room full of flies and chasing them with a fly swatter trying to kill them one by one. Actively running GFO is like hanging 30 strips of fly paper and letting them come to you and catching them all.
After switching to the reactor linked above it is like a night and day difference with excess nutrients. I have it in the rear chamber of my Biocube 29 Best purchase I have ever made for my tank and would recommend it to anyone with a sumpless AIO. Cheaper and more effective.
Just my .02- Both are expensive and not worth the $
Edited by JDK, 02 April 2012 - 02:51 AM.