Ye heard same story as yours over and over again.
Been collecting material all over the web the last 3 days and havent found a single grow from seed to harvest with these tents. Have about 100 threads found now about problem ones though. Some people have managed to go through 12/12 phase but with poor yield and even they are ery few.
One guy even made clones to try it out properly and put half in the hut and half in another tent with same nutes and same lights etc and got less than half the yield from the Hydro Hut ones.
Some plants seem to be able to take the tents better than others though. On ordinary growforums you find much less problems but on CB forums as I said after 20-30 hours of research I am yet to find a seed to harvest grow that went ok.
I changed my tent for a Secret Jardin Dark room and my dieing plants recovered in 30 hours.

Chinese poisonous crap canvases.

Puffzter