Have you tried fishless cycling mate??
http://www.discusforums.com/forum/viewtopic.php?t=895
Have a read through it and if you have any question, shoot. Makes things a bit easier because once completed you can load the tank up with all the fish you want.
The cycle your doing atm, might not produce enough bacteria for 4 discus and might create ammonia which can be fatal too them.
Just trying too save you trouble in the long run, also alot quicker.
Then if your tank is ready and your not ready for fish you can keep the bacteria alive by adding more ammonia.
Just remember too keep it out of reach from the kiddies and look after your self aswell..
Cheers
Scott