mcease, sorry for the late response. For some reason this site wont run on my work computer when I have the most time to check boards.
To answer your questions, water is great, I change about 50% every Sunday and Thursday. Sunday gets a thorough gravel vacuum adn algae cleaning(if needed) and Thursday is more of just a water change. The fish are a mating pair that have been together in my tank for almost a year now. They have spawned about nine times in the year. They currently reside with an 8" pleco who they haven't killed yet. As for how they get along? He basically beats the heck out of her every chance he gets for a few weeks until she decides to spawn again and then all is peaceful for a month while they spawn, hatch and gaurd the next batch of fry. As soon as I remove the fry the beatings start all over again. Sometimes he doesn't even wait for the fry to leave before he wants to spawn again.
Getting back to your original question, don't get me wrong, I'm not knocking biowheels or canisters. If someone has good sucess with them, cool, more power to ya. My point was that with big nasty pooping fish like these, or oscars, you want maximum "mechanical" filtration, as easy to clean as possible. It takes me probably 2 minutes (if I'm lagging) to clean one of my AC300's. Its just a quick turn it off, pull out the media basket, rinse the sponge off in a bucket of tank water and pop it back in, good to go. They also have a little known feature where they will tell you if they are getting plugged up as a small stream of water will start trickling down two channels next to where the uplift tube enters the filter.
Hope this helps and good luck.
;D