Yellow new buds

Hey guys,
A little help is needed yet again.
I have 2x cheesewreck & 1 Church growing in coco under 600w HPS on 12/12.
Please take a look at my pics & tell me how to amend these sick girls.
thanks for taking the time to help.

how close are your lights?

doesnt seem a whole lot wrong, but pics under HPS are shit..

flush them, get ur pH right and back the lights off and all shall be good my friend..

shalom.

Hi Green, Hi Streetlegal,
My lights are 8" off the plants, but are cooltubes sucking from freshair vent through light to fan & out though chimney.
i can hold my hand above the plants with out getting burned, so i thought this was ok as more light was better ??
Take a look at pic 3 & 6 see how pale the leaves are & the newly forming bud ?

ok, im starting it here, im dispelling a big myth about 'more light is better'.. ok yes more light is good blah blah, but there is a point of overkill, remember these are plants, living things, they react to the environment, when pushed too hard, too soon, undialled, they get sick, so wot do ppl do?? MORE light! MORE nutes! MORE MORE MORE!..
back the lights off, treat them nice.. i can TOUCH my cooltubes, tho if my tops get too close they still get bleached, its just too much for them..

how far 12/12 are they? how old are they? ppm and ph?

the way to fix coco grows is to flush, ph nuted water (lower if its too high) back the lights off, and dont over-water., then wait, it wont take long.

Hi, streetlegal,
the plants are 9 or 10 weeks old from seed, they where veg'd for only 3 weeks before going into 12/12.
the ph is now @ 5.8, but when i started i was setting it at 6.2, until i was informed that was too high for coco.
I have had a problem with the pale leaves since week6, but that turned around after i flushed & gave them 1st some magnesium (epsom salts) then nitrogen then iron sulphate.They all got better, apart from 1 cheesewreck
i thought i had sorted the problem out on the 1 cheesewreck & the church. then the church started striping on the leaves as the buds appeared. now my buds are turning yellow/ white. i was wondering if it was zinc deficient ??
the 2nd cheesewreck has had pale top leaves since wk6, but i haven't managed to get rid of the problem. it has got slightly better, but now seems to be getting worse again!
You say raise my light, how far off the plants then ? does light really bleach the leaves ?
should i fush them again while flowering or not ?