ok...three posts in a row.....now i'm just being a thread hog...but I just thought of something else.....
ideally, you could connect three (or four or however much media you have) of these gadgets together and with a strong enough powerhead/pump you could push the water through them.......
the more I think about this the more I want to try it....it sounds so much asier to change the media in something like this than to change media in a filter bag....and less bulk in the sump because you can keep the housing outside the sump......
I'd have one with carbon, one with phosguard, and one with????? well, you get the idea....
I'm also thinking you can pull this little project of with PVC tubing, some screw on end caps, and some vinyl tubing....only drawback is that you wouldn't be able to see your media......