Light distance

hey there i got my 400 hps 12 inches from my plants is that good enough they seem to take it well for the last 6 weeks in flower but now all my fan leaves are yellowing someone said something about light bleaching any one heard of this its 12 inches from the one and like 15 from the other just trying to figure outwhy my leafsare doingthis in week 6 already i know they have 3-5 weeks left i dont know what the hellin going on fox farm nutes

Do you have any pics? I run my 400w at about 10-12 inchess above my plants with no cool tube and they are fine. Hold your hand under the light at canopy level, if it is uncomfortable after a minute or so on your hand then it is on the plants too. Are you sure the yellowing is not caused from the later stages of flowering? Unless you are running a sativa dominant strain, most indica's are done in about 8 weeks. At about week 6 or 7 my leaves start yellowing dramatically.

i have my crop right now 12-10 inches away from a 1,000 watt hps, and they usually end up closer then that to the light, so you should be cool. when in doubt do the hand test, too hot for hand, too hot for crop