i've a 1.2 x 1.2 x 2m secrec jardin tent 2 nl5 x haze a 400hps on 11 off 13 in my garage , i keep them oh at least 3 foot away from the lamp and try not to stress the leaves when its closer or indeed it slows the plants up ,i find if the back of your hand is uncomfortable then the plant won't like 12 hours being there too close either,