Need Help! Can't Pin point Problem!!

So it seems I have lower leaves spotting, red stems on some, and yellow tips on new leaves...
I will post pic's
4th week Veg

Hydroponic, using AN ph perfect grow and bloom...But only grow A/B right now...
Light source (400watt Hps) is atleast 18" away from tops...
RO Water...

I am lost someone please give me some advice on a solution...it seems like a combination of issues!

Do you have a meter? What's the ppm and Ph. Are u using full strength nutes. If so cut back to 1/4

dankshizzle said:

Do you have a meter? What's the ppm and Ph. Are u using full strength nutes. If so cut back to 1/4

Click to expand...

Yea the PH is about 5.6 and the PPM is 374... I have been gradually doing an increase on nutes...right now its 14ml of A and 14ml of B in week 4 in a 3 gallon tube...

Really need help Had to bump this!