Are these full grown discus or are they juveniles? Best to grow out young discus in a bare bottom tank because the constant feeding will quickly foul a planted tank, you just can't clean up all the missed food. If they are adult or wild caught adults, then a planted tank is fine, is you have enought to "distrubute" the agression. (Not a discus person yet, but I've looked into it quite seriously.)
Have you tried City Pets (Beechnut at Beltway 8 ) for Eco-complete? They also have the best price for flourite, I think.