Beneficial bacteria is a must for your medium (pirahna and tirantula are Microbial and bacteria)Your plant with grow MASSIVE using this the little critters eat the stuff you feed plants and there waste is GREAT for your roots.
Download these PDF a must if you want a GOOD grow
PH Manifest http://www.growersunderground.com/blog/hydroponics-videos/ph-manifesto-your-buried-treasure-of-growing-secrets
Grow room tips and Tactics http://www.growersunderground.com/downloadtipsandtactics.html
Voodoo juice is pretty much sex in a bottle, for your roots. The man who taught me the most about growing always told me one thing " Always jam out those roots brother. You give them bitches some Voodoo and Carbs, and your shit will be obviously ridiculous. Period dot com."
I use Voodoo with Liquid Carbo load for Veg, and switch to bud candy during flower. Carbs carbs carbs! Oprah would die!