Discus Tank Advice

Hello,

I have MTS in full swing, and have the go-ahead from the spouse to set
up a large (90+ gallon) discus-only tank. I currently have a 50-gallon
bowfront with angelfish, 2 gouramis (1 gold and 1 pearl), cory cats,
cardinal tetras, and 2 ottos. In a 10-gallon divided tank, I have 2
bettas and 2 ottos, and then one other betta in a 5-gallon Mini-bow.
Every fish has been healthy and happy so far - I do 20-30% water
changes each week, and feed a rotation of live, frozen, and pellet
food. However, I have never tried a planted tank, yet. I plan to do
this with the Discus, though.

I am wondering if anyone could recommend some books (or email groups?)
for keeping discus. I love these fish, but I know that they are tricky
to keep. I currently use RO water in all my tanks, buffered with Kent
R/O Right and a tiny amount of Chichlid buffer to bring it to 7.0 ph.

Any advice or information would be greatly appreciated!

- Lisa