Looking for Help - Nutrient Deficiency check out pics

Hi all,

I have a Turbo Garden Ebb and Flow hydroponic system. I've read a few books on growing, so am relatively knowledgeable of techniques and growing steps, although lack experience.....this is my first grow. I'm using a 300W LED light I designed (I'm an electrical engineer) and built. It is configured for 430, 470, 630 and 670 nm light output, which should be optimal. I also use a 150W HPS for side lighting and to supply other spectrums needed for optimal growth. Growth has not been an issue....the plants have grown very quickly.

The issue is that my plants will go through periods of everything looking great and then I start to get the issues in the pictures, which is an obvious nutrient deficiency of some sort. From what I've read and seen, it looks like K or Mg deficiency (or both). Anyway, I was wondering if anyone else had an opinion on this. My thought is that the LED lights are supercharging photosynthesis and hence Mg (the "spark") is being used up quickly. I am using GH Flora nutrients and following feeding plans that others have had success with. But, I'm thinking I need more Mg.

Another, possible contributing factor is that I'm using tap water at 210 ppm combined with distilled water to produce a starting water PPM of around 150. It is possible my water has high calcium (I know my pool gets loaded with it), but I haven't had it tested. I do use GH Hard Water Micro though which has 1.0% Calcium instead of the normal 5.0% Ca to account for the relatively hard water.

Thanks in advance for your advice! It is much appreciated.
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Originally Posted by kathie420

I am having some of the same issues. I believe it is a high calcium level as well because I have white residue on the drainage holes of my pots. (Used to have it on my fish tank equipment as well). I tested my soil and it registers a 7 on the meter. When I used the seperate vials my ph, N, P, K, are all neutral or med. I set my tap water out for at least 24 hours and always have to use ph down to get it between 6 and 7. Hopefully someone can advise on how to correct the issue.

I've been using the following: 5ml CalMag Plus / 5 ml Grow / 7.5 ml Micro HW / 10 ml Bloom per gallon and it has solved the problem. Growth is unbelievable now with many, many secondary off shoots. I think I was just underfeeding them for the LED lights, resulting in multiple deficiencies.