i have 4 hydro plants under a 400 watts h p s light, 2months in to flower almost, the o n a works great. in my hallway i have two ozium auto sprayer( ok at hydro stores and amazon they charge 50 to 70 bucks for two things of ozuim and one of the sprayer things! at wallmart you can buy the air wick timed sprayers come with one can air wick, safe the top from the air wick, not the cap but the sparyer and put it on the ozuim, 12 to 15 bucks that way) o n a is great, try the bucket dude, 9 cups water one cup ona gel and one cup soil moist but some holes in the bottom of bucket for air to leave when you attack the fan. if you cant drill and cut in to walls like i cant its the best way to go