Whats a cool tube?

I'll be starting a grow next month and really need some help with lighting it all confuses me.. I've finally figured out HPS seems to be the best option for me in terms of the lumens emited and the cost of electricity but I've been recommended to get "cool tubes" could anybody explain what they are? I'm going to opt for a 400watt HPS I think or possibly a 250watt HPS depending on what people say. The area I'm growing in is about 3x3 feet and I recon I'll probably put about 2-3 plants in there would 250watt be enough for this? if I decided to opt for the 250watt above the 400watt would I see a considerable loss in crops considering it's a pretty small grow? Also I'm gonna buy a grow tent you know the ones that supposidly stop the heat signature? for the reflectiveness aswell but mostly heat thing choppers like to fly over here thought I'd mention that as the insides are highly reflective so I figured maybe 250watt would be ok? One more thing, the tents I've seen have a place to add a exaust to the tent to keep the temp down would this be worth doing for my small grow and would I also need a fan aswell as a exaust? cheers for any help

A cool tube is a reflector that is a clear tube, open at both ends to allow you to pull air through for cooling. You can put an air filter (carbon/charcoal) on one end and in line exhaust or centrifuge fan on the other to rid the smell and cool at one time. You can just duct it to the tent exhaust exit if you go with a tent. They're great for keeping your temp in check. You won't need a tent if you're just trying to eliminate a heat signature. A 400W isn't enough to identify as a grow op. It's cool if you want one anyway but not needed to stay off the scope. I'd go with the 400W over a 250 since you can get the 400W almost for the same price as the 250. More watts = more yeild. Veg with a MH and switch to HPS for flowering, unless you get one of the full spectrum bulbs that is half MH and Half HPS. Some go all the way with MH and some use HPS all the way, but it seems most people have reccommended mh for veg and hps for flower so I tend to go with the majority. Hope this is the answers you were looking for.

Thanks for the reply man appreciated, I think I'll go with the tent it seems less work and I'd still be para without it lol. Thanks for info on cool tubes I was actually going to get a carbon fan thing although I thought a cool tube was some kind of cooler light lmao.. Would a 400watt be considerably more to run in terms of electricity than a 250watt? I have a meter for electricity that you have to top-up so I don't really want it to go through the roof. I got a little baked tonight and decided I'd plant a couple seeds and leave them in the window as the weather has been good lately until I start my grow with my student money next month lol you think it'll be ok to just transfer them to the grow room next month when its ready? thanks

I started mine outdoors and transfered inside after three weeks without a hitch so I don't see why not, although it would have gone a little quicker inside under the lights for longer light periods with less stretch, but I had a streetlight helping out at night. A cheap way would be to leave them outside during daylight hours, then bring them inside and stick them under some cfls(compact flourescents) at night. It's better to veg with at least 18 hours of light. Get some 26Watt in the color temp around 5,700k or higher for veg, around 2,700k for flower. They work great when used with a hps during flowering. If you decide to do a full blown, inside grow from start to finish, you'll already have everything to do it with next time. You shouldn't see much difference with the 400W as far as your elec. bill. If you can afford it, get a light with an electric/digital ballast. They're more energy efficient, have less wattage loss, and are quiet. If you get a HPS ballast, you can run MH or HPS.