two tomato problems

[sfambro]

New the forum and have looked at prior posts before I posted this. Here's the questions:
1) Why are by leaves bleached looking (see attached 'chlorosis_maybe.jpg')
2) Why the yellowness around the edges of another plant ( see 'no_idea.jpg')

Here's the facts:

1) Flora gro/bloom/micro mixed as per GH directions
2) TDS 1170 ppm
3) pH ~ 5.9-6.0
4) nutrient temp ~ 22 C
5) Grow area temp ~ 28C lights on, 19 C lights off
6) Co2 ~ 680- 720 ppm
7) There are 7 bush tomato seedlings in the hydroponic grow area
8) 2 X Quad band UFO led lights (180W total) about 18 inches from the canopy, plus 4 T-12 GE plant and aquarium bulbs
9) 5 nutrient feed cycles per day, about 10 minutes nutrient flood time each cyc
10) No sign of pest infestation
11) Lights on 20 hours, off 4 hours
12) Plants have circulation fans

Any ideas?
Thanks

-s

[GpsFrontier]

I am no expert, but to me it looks like either a nutrient deficiency or toxicity. I use natural lighting myself and am not real familiar with using artificial lighting, but it sounds like the combination of LED and florescent lighting would be sufficient, although I don't know anything about the output of aquarium lighting. But insufficient lighting usually results in the plants becoming elongated and leggy. Then if no pests or fungal diseases are NOT a factor, I would look at it either being a nutrient deficiency, or toxicity as the problem. This could even be a result of water quality as the nutrients can bond to other elements in the water, and become bound up and unavailable to the plants (causing deficiency's), or excess elements in it could cause toxicity.

The build up of the TDS (total dissolved solids/salts) and/or minerals in the system, as well as the growing medium can cause nutrient lockout, even if the nutrient solution is perfect. TDS readings just tell you the total, not witch elements are present, and in what quantity's each are in. Just the total amount that's dissolved in the water. Any buildup in the growing medium is NOT dissolved in the water, but is still in contact with the roots and could cause nutrient lockout and/or toxicity.