sorry to say but most would consider that tank far too small for 8 discus, i would go with no more than 3 or 4. even then you will be doing a lot of water change.
dont want to be negative, but its easier to hear it from someone else rather than learn the hard way. its very discouraging when your beautiful discus start dropping off one by one, for what seems like no good reason.
on a positive note, if you end up with a pair, your tank will be a good size to breed in(the discus i mean)