First off...Welcome to AquariumAdvice.com!!!
I would say the first thing to do is identify why you were having so many problems with your 30 gal
so you do not repeat that with your new 90. Using the 30 for a sump is a great idea. As far as substrate goes, LS
seems to be the prefered substrate out there right now. It helps in water parameter stability and needs no maintanance (CC
requires more time and attention). You will not beable to avoid a cycle by using the exsisiting water. The beneficial bacteria that you develope during a cycle live in the substrate and on the LR
, not in the water. I would just start from scratch. As for pumps...3 Maxi-jet 1200 powerheads in the main will provide you with great movement and a Mag Drive 7 or 9.5 will be a great return pump from the sump. I might also suggest gettinga good book if you do not already have one. I like "The Conscientious Marine Aquarist" by Robert Fenner. Check out www.liverocks.com
for some of the best LR
available. Good luck and keep stopping by AA! Lando