I would recommend thinking very hard about venturing into discus if you think you won't have the time to change the water more than once weekly. They are not like other freshwater fish. They are extremely high maintenance.
They require stellar water quality, large tanks (you might be able to fit 2 in a 55 at the most), and warmer water than most tropical fish (You'll need a reliable heater that will keep the water around 81 or 82 degrees).
In all honesty I'd try just a community tank full of a lot of little pretty FW fish instead of attempting discus. They should only be kept by hobbyists who are truly devoted to keeping them and can spare the time to maintain them properly.
_________
55gal,216 watt Tek T5, 45#LR, 45#LS, 3 maxi-jet 900's on a natural wavemaker timer,phosban reactor, 5 gal fuge (built out of standard 10 gallon tank) with chaeto and feather caulerpa, sealife systems protein skimmer, wet/dry, 3 blue/green chromi, 1 skunk cleaner shrimp, 1 coral beauty,1 scopas tang, 2 false percs, 5 mexican turbo snails, assorted dwarf blue leg hermits, astrea snails, and nerite snails | 
Discus 
90g plumbed to basement,75g sump with 10g refugium inside,250 Aqualine skimmer,QuietOne 6000 for return,HydorKoralia's #3 #4,2 kind zoanthus,3 kind mushrooms,pulsing xenia,yellow polyps,Sailfin Tang,coral beauty,sixline wrass,lawnmower blenny,Kole Tang,royal gramma,firefish,snails,hermits,crabs,serpent star,large feather duster 
