Looking to make some major changes, and I need your input.(good-bad-whatever)

-Current system
Oceanic 240 (8x2x2) with matching Oceanic Stand. est. 8/04
Mixture of Zoas, LPS, SPS, and Clams
approx. 50g sump with built in fuge and 2-6"x30" skimmers

-Problem with system
My large Gigas Calm is blowing water out of the tank regularly now, and I am tired of cleaning/drying it up. And if this water happens to hit my light fixture it could be dangerous if my children are near it.

-My Idea
Get rid of the 240 tank, and go to a 150 (4'x2'x31")and put 2 freshwater Starphire 80 (2x2x31") to bookend the reef. I have never really had a freshwater tank, and I would like to do a nice planted Discus and German Blue Ram tank. I will keep the same Oceanic stand, and all of the filtration will remain the same for the reef tank.

- Some Questions for MAASTards
Should I drill the freshwater tanks, and incorporate a sump with them?
Can I use DI water in the freshwater systems?
What are some challenges to lookout for with freshwater planted tanks?
When is it necessary to dose CO2?


Troy