Give me a sec to finish rolling this duber, smoke it then i'll be right back.............................................. .................................................. .........................................5 minutes later............................................. . :stoned:
Ok, you asked and i have some time to kill. I'm not a pro but i will share what i have learned so far.

Your rainforest system has six sites for six plants. You can use them all from seedling to full maturity. Nutrient change is every 7 - 10 days (its up to you). Keep the water level from dropping below the lower water level line. I try to keep the water level toward the high level mark by adding fresh water with nutes every other day or every day depending on how much they drink. If your ppms go higher than the feeding chart suggests then you should give just Ph'd water on the next feeding. Do you have a ph tester?

The rainforest system does not run hot. The temperature of the environment you have your system in causes the water temp to increase. Do you have an exhaust system and fans blowing on your plants?

Your grow space is fine for the one system that you have. You can grow all six in that space. Think maybe single cola plants. As for having one plant at 2ft tall and the rest at 8in, its a good idea for all your plants to be the same height but thats also up to the grower. I don't know if you've tried cloning with your system but i have had a 100% clone rate so far with this sytem. Thats one thing this system IS good for. As for the rest we shall soon find out.

When talking about lighting what you have now is keeping them alive but if you want them to produce a decent end product, you need HID lighting. HPS is preferred for flower and metal halide for veg. Hortilux HPS bulbs can be used for veg and flower. A 250w HPS would probably be good for your space. With exhaust and fans running you shouldn't have any heat problems.

Nutes, not only do you need to use N-P-K but also need to use boosters and supplements to produce with this system. Very important because a plant cannot grow by just drinking water with only n-p-k in it. Along with your system, did you get a "Weekly Phase Feeding Chart"? In that chart GH gives you options of how you can apply what nutes and additives at what phase. What type of water are you using?

Odor is going to get stronger during flowering. Get a good exhaust fan with a good filter at the end to scrub the air clean.

I hope this helps you a little bit. And i hope you have the $ to spend. A wise man once said that if you go cheap, you grow cheap. Wise words to think about. Happy Growin!!!!!!!!!!!!1