spotted and faded leaves

Hi friends, it's a long time I don't write here, hope your cycles were very productivein the meantime! I open this thread because I've again a problem, but I start from the setup:

RDWC system with 4x20L pots
70% RO water + 30% decanted tap water
Ec base 125uS
ph 5.5-5.8
Ec 650-850uS
water temp 18-20 (chiller)
nuts: AN Sensi expert (previous cycle I used Conoisseur but I had the same problem anyway)
Temp 21-33
Rh 45-75
Light: MarsHydro 900 + Apollo 320 (chinese copy)
week: 2/8 Bloom

I've again a problem (I hope it's only one...)

un the mid-high part of the plant the leaves are faded somewhere, at the beginning it seems like a different shining of the leaf in a small area



Other leaves have a bigger coverage



In the mid-low part of the plant there are very small spot near to the leaves edges



going down the situation is worse



degenerating in the very low leaves



In the previous cycle I thought the problem was a Ca deficiency (I was using only RO) and I added calmag but I never solved the problem and I had a very poor harvest. This time to prevent it i mixed RO and tap water but the problem is still there.

Please help me to resolve this enigma, my heart cries due to the knowledge of what is the future if I don't resolve it

sorry, I think it's in the wrond section, I'm opening the thread in the Growing questions area.

Please Admin could you delete this thread? Thank you.