I also heat the room and not the tanks (other than a few) - there's a furnace with a duct into the room and I keep it cooler than most.
You can either heat particular tanks (for fish that prefer warmer temps, as I do)... or you can heat the sump (and all the tanks will be roughly the same temp). If you heat the sump, you're going to need a bunch of wattage. I'd cover the sump both to keep heat in and to reduce moisture.
I also wouldn't take the sponges (or in my case boxes and sponges) out of tanks when you add the sump. The extra circulation is a good thing and is a back up if the pump for the sump goes out.
The nice thing about rubbermaid stock tanks is the drain in the bottom - a great way to do water changes and otherwise keep the filter clean. With such a big filter, it would be easy to let it go and get really grungy. I'd rinse and clean regularly (keep a filter sock or something to keep waste out of the bio area).
And, of course, you'll want to plan a way to keep tanks off of the system for quarantine and treating sick fish.
Matt
Okay so I'm looking to redo my racks for my 10 30brs and eliminate using sponge filters and heaters in each tank. I'm planning on getting a 100 gal Rubbermaid tub to use as my sump. I already know how my design is going to be but have some questions.
First question how many heaters and wattage should I go with to heat up all 10 tanks.
Second question what are the benefits of going with a sump.
I posted this elsewhere and getting mixed reviews. Thanks