Plant is pale and leaves are twisting

Hi, I think she's hungry. I'd feed her more.

@xbrico, thank you for your answer! Yeah, I was also thinking about a immobile nutrient deficiency. I bought cal-mag but didn't add it to my reservoirs because I've read somewhere about these Green House Feeding nutes that they don't get along well with cal-mag product for whatever reason (I can't remember it right now) and I wanted to wait a bit until the plants are more mature so I won't lockup any of them in their intake. Nevertheless I'm also leaning towards the idea of adding cal-mag to my reservoirs now because they've got so much bigger in 2 weeks and any should be fine with the addition ot it (I still have to update my diaries tho :P ) XOXO Cremo

@gmslave - know you have some great experience in this area but thinking yellowing of new growth...one of the immobile nutrients maybe (Sulfur, iron, Calcium)? Really looks like a Sulfur deficiency (From the pics and the "Stock Pics" of what a S deficiency looks like) or Iron but I am leaning towards more sulfur being the problem - which is actually quite rare!!! A good CalMag would be the cure if you're not using one as it would hit the 2 potentials as nearly all CalMag's are usually Calcium Nitrate, Magnesium Sulfate and Iron. Calcium also helps the uptake of those 2 nutrients you potentially look like you need so worth a shot...esp. if you're using RO water. Hope this helps and it improves soon!

@gmslave thanks a lot for your input. This particular plant is the only one that's not an automatic, it's a "regular" feminized plant. Other than that I use the green house feeding nutes for the first time. All automatics are growing great, just this regular one has problems which is kind of strange because they automatics should have a harder time with a 500ppm, and when I gave em half of it, all went pale in a matter of a few days. That's why I increased the nutes. Any other suggestions?

I always used Dutch nutrient formula, DNF, for hydroponics, as it's a nice clear nutes and was made specifically for hydroponics. Cheers