Hello Sugartwist,
90 degrees is way too high. Get something similar to this
CLICK HERE so you know what your temps actually are.
Most hang their thermostat at plant height to gain an accurate reading. That is really high temp for fluorescents. Preparation of the grow room... lighting, temps, humidity are your first priority. Get the temps under control first. Forget the humidity unless it is at an extreme : below 20 percent, or above 80 percent. 50 percent is ideal, but within this range you will be fine. A fan can only move the surrounding air. So if your surrounding air is hot a fan will not cool it down, just push it around. You need to vent the heat out, or get the room temps down with AC.
Perlite is a soil additive
INFO HERE Mix it with your soil to improve water drainage. You want your soil to hold water, but to drain well also. You dont want heavy, thick, compacted soil as this will smother the roots from oxygen.
I recommend spending 15.00 and buy some soil. Fox Farms Happy Frog is giving me wonderful results. Fox Farms Ocean Forrest is very popular too, although many mix with Fox Farms light Warrior at a 2:1 ratio as some say its really hot( a lot of nutrients) and will burn the plants. These soils are organic and contain perlite along with a myriad of other wonderful stuff your plants will love.
As far as nutrients I would recommend something simple that has been proven effective. Check this out
THE LUCAS METHOD You may want to try Maxi-Bloom... 2lbs $20.00. simple, cheap and effective. I am currently using General Organics Go line nutes. Very simple, and effective, but a little more expensive $35.00 for the GO Box which contains the complete line. Here is Happy Frog soil with General Organics go line nutes at 4 weeks flower. I only grow 1-2 plants at a time for personal use so I am aiming for high quality. Cant wait to taste this