I bought a hydrohut type of tent a while back before this grow started, and when i began everything was fine for about 2 weeks, and then my plants started to slowly yellow, and start do die. I took the vinyl off of the frame, and replaced it with mylar n panda film, and the plants INSTANTLY perked back up n got better. Its the TENT dude, not the heat.
Basically what it is is, there are only two machines that make pretty much ALL growtents being sold today. One machine Makes HydroHuts, and some generic versions, and Homebox's. The other machine makes Secret Jardin, and Darkroom. The machine that makes Hydrohut decided they would try using a different bonding agent in the vinyl to make shit hold together better, while cutting down on expenses at the same time. It was an FDA approved material, so they figured it wouldnt kill any plants. This happened in late 2007, and early 2008. They ran off a couple thousand of these tents in one single run. Basically what happens is, when the light gets hot to a certain point, it causes the bonding agent to "Off Gass" a toxic chemical, while not poisonous to humans, it is LETHAL to plants, slowly killing them off - yellowing at first, but then straight up wilting and dying within a matter of a couple weeks. Hydrohut is the only company taking responsibility for the matter, and is offering to replace anybodies vinyl that is toxic, but it has to be a Hydrohut. Anyone that purchased any other brand is pretty much screwed.
If your gonna purchase one, make sure its a new one that your hydro shop has just purchased and stocked, so you dont have to take that chance. If youve already purchased one, then i guess you could wait until you start to see yellowing in your plants reguardless of the fact that your doing everything else perfect, and then take the vinyl off, and replace it with thematerial of your choice. The plants will not only recover, but theyll thrive and youll see just exactly what a growtent can do for your plants -- which is ALOT man, im REALLY impressed with the way tents work, and ill be using a tent in every grow from now on, for my mothers
If you got a DarkRoom or a Secret Jardin, your fine. Those tents were made by the other machine in hong kong, and they didnt use the bonding agent. So rock on with your bad self if you made the right choice, lol.
Hope that answered all your questions man.