look at these pics please

plants are 6 and half weeks and leaves have turned like black purple within a few days i have two strains together in same hydro feed and only this strain has turned this colour p[lease advise thankyou

what strains are they?
why are there 2 ion the same hydro bucket?
not all plants need the same nutrients
take more pics when the light is off so we can see the real color not just yellow

Wow, if that second pic is with your HPS light off . . . those are some purple leaves. I haven't ever grown in hydro, but I'd say you gave them too much fertilizer. Someone who has done hydro can probably tell you more, but you should post your feeding schedule, what ferts you use, ppms, ec, pH, all that stuff so the people who know can help you better. Also make sure your HPS light is off for pictures!

Im not a hydro guy either but it could be way to much Nitrogen. Ive heard that will cause some purpleage.

i been using flora 3 part nutes and in the last four weeks of flowering ive been adding some hammerhead pk 9 18 ,ph set to around 6 ec around 1.8 but my ec has been rising and ph dropping for a while now gets better when i flush em out i think nutes are building up in the rockwool the strain is kings kush and el nino feeding from same resevoir all pics with light on thanks

i have just seen that kings kush turns this colour when nearing the end so think im just fretting for nothing sure smells sweeeet