deacon,
I am also considering that. Some of the posts that I have read claim that a resin sand bed looks good at first but after the biofilm grows on it, it can't be cleaned like a BB or sifted like real sand.... ?
Here is an update on my progress. As though one hole inside the cannister filter wasn't enough

, I drilled it again and added a hydor 50w heater.
I went with the hydor because it was the shortest one that I could find and I like that fact that I can just bolt it to the underside of the cannister top out of the way. I have heard mixed reviews on this heater so I will be running it with an electronic controller to manage the temp. I made the holes just barely big enough to squeeze the wires through and then used a hole tube of silicone to seal it all up - cause dang, 7.5gals would not look good on the floor of my office...
- Chad