help required

2 X OG Kush in NFT45 litre. on PH'd(6.5) water, were nice yesterday, today looking yellowed and drying of leaves. Quite precise temp control(88 F light at 2 .5 feet. mmmm , used ph down to ph my left out for a day or two tapwater. they are in jiffy 7 pellet rooted 2 - 3 inches out of jiff7 pellet, put in 4" rockwool cube and transfered to veg. 400w hps..

I cant think of any more info, cleaned out res and all equip..... this one has me stumped folks.. please help

ph should be down at 5.8 i would say 6.5 is too high.

i try to keep my temps down at 75f-80f

5.8 is for hydro, 6.5 is for soil.

My soil girls are happy all the up to 6.8. Are you pumping in co2? if not 88 is high. 78 would nicer without added co2

But dro get your ph down. I bet thats why theyre yellowing

cheers lads, you are all legends