I have a HOT Magnum - although it is now "retired". One thing you can do to keep the micron cartridge from getting clogged too soon is to use a sponge filter on the intake tube. The company that makes Hydrosponges is the one I used. Having said that, I went to Eheim canisters. Kelly Beard, Cat IV, Team Allanti President, Allanti Cycling Club - http://www.allanti.com I/T, IBM Global Services