HydroHut was aware that they had a problem long ago, and they had a remedy up until May 15th 2008 where you could send the canvass back to them for a free decon, it just took them 3-4 weeks to get it back to you. The china made canvass lining definitely out-gasses an oil distillate which will poison "sensitive" plants,(per my speaking with them). I had them do mine but it will still effect some strains today, seemingly the more spindly sativa strains. Yet other strains do fine, its a crap shoot.
As the HydroHut remedy is no longer available, you should return for sure if thats an option you have. Sorry I also was not yet a member here to post this stuff prior to May '08. They have it detailed on their website way down at the bottom of the page under "Commitment to Quality" tab. Here's a link:
Quality hydrohut to save plants killing in hydrohut growing.