Plant Suffering possible nutrient deficiency

I am growing in an indoor deep water hydroponics system. I have 2 air stones running 24/7 to ensure the root system has enough air. I light using 2 125 watt CFLs on a 18-6 schedule. At first I thought this might be an iron deficiency, but after adding iron and a few weeks with no change I then considered it might be a potassium deficiency. I added water soluble potash but have not seen a change. Please help. Thanks

Looks like nitrogen to me, as far as I've seen potassium looks nothing like that. I would change your res, and put in grow nutes at 600ppm as well as cal mag and see how it goes.

Thanks I will give that a shot.

I don't grow in hydro just so you know, but that looks like magnesium deficiency to me. The CalMag will help correct it.

I thought it looked like mag deficiency as well. You can also foliar feed with Epsom salts for mag. Good luck.

What is the pH and EC of your nute solution?

You'll want a pH of 5.5 because as a plant feeds the EC drops and pH rises allowing all macro and micro nutes to be taken up by the roots.

When pH rises above 5.8/6.0 it's time to lower it back.down to 5.5

Keep EC between 1.0 and 1.5 or if you use a ppm/tds meter,between 500 and 1000 ppm.