Yellow spots in indica 6th week flowering, help please!

Hi folks!

I have 5 sensiseed indica's mix in the 6th week of flowering, however only 1 is showing yellow sopots in the fan leafs, from the middle to the top, the tips are a little curl under, and the bottom leafs have yellow tips, the other 4 ladys have the tips a little bit brown.(see photos) Here's the setup:

• Seeds: Sensiseed indoor mix.
• Day temperature: 70°F. (12 hours)
• Night temperature: 60°F (12 hours)
• Fan: 12 hours in slow.
• Humid: 55%
• Light: 400w HPS and 3 26w Reptiglo 10.0 UVB
• Nuts: BC Pure blend bloom (50%)+AN Bigbud (25%)+AN Bloom booster (25%) at 850ppm in dripper system.
• pH: 5.6

Any comment or suggestion would be very appreciated.
Thanks a lot for your time,
Cheers!

hi
did u try switchin' the places of the plats
is the fan close to this plant
i'm growing under HPS /900w/ too
but my fans are working non stop i'm in the 1 st flowering week with mine plants.
i guess u gave the same amount of nutes and water to the plants, and only that give that reaction ??
and that night temp. is about 15 C, it's kind of low but on the other hand indicas are pretty tough so that probably isn't the factor
if not other try to lower the nutes a little bit - maybe it's nut burn
when i get something on my plants i start changin' shit and watch how it reacts to the changes - worked pretty good 4 now.
hope i helped. peeeaacee
ooo and keep in mind that in flowerin plants leaf do turn yellowish it is natural

because you are in the 6th week your plant are any goodness they can out of the leaves they will end up been totaly yellow thats when i pull them of the browning is prob because your plant know its nearly time to give up the crop dont worry both these thing happen to everyones growups.you dont mention how the bud formation is comeing along should have a little structure to them by now its at this point alot of people who i have seen grow drop clanggers wanting to rush there plants through so they can taste the goods wait for the tricones to turn be4 putting on water for a week to many people read a packet and it says 8 week so that what they do at 8 week chop even if they left a little longer the crop would taste and be alot stronger.but it souns to me has though everything is going to plan i have some blueberry at 5 week and its smells so nice looks so good im gonna have a nice pipe of that then wash it down with a thai super skunk its a hard life