i have never done hydro grows. but, i do get slime, in my rapid rooters and dish. i have em sitting in water, and i get slime. i dont think its harmfull. a piece of newspaper, layed on top, for a moment, removes it, tho. also, where there is water and light, there will be algae. plants look good. cfls work well, considereding. i have never thought why one ounce i got such good yields off five god bud. 3.5 oz ea. but, as i remember, i had only one 600 light at the time, so i surronded the edges of the grow, with four large cfls, and their own mini hoods. got em for 15. ea at home depot. also, got hood and cord, for 9.95, at same place. they are huge. and, perhaps this was why i got huge yields. i was also using the foxfarm lineup. hmmmm. i have used many differnet nutes. with no real diff between them.......