Help identifying problem

[Brandon3423]

Hello all, first time posting here. I've been playing with aquaponics this season and seem to be having either a disease or (more likely) a deficiency. I think it's either iron or magnesium but would love some input! Thanks in advance for any advice.

 

[headfullofbees]

I have seen similar damage to tomato leaves caused by high winds, but in any case, a magnesium deficiency (which it also resembles) is best overcome with dilute Epsom salts, although I am not competent to advise on aquaponics dosage.

 

[alp]

I am no expert. After googling, it could be powdery mildew

http://homeguides.sfgate.com/white-spots-tomato-leaves-leaves-falling-off-79419.html

And here it suggests that it could be something fungal or mineral deficiency, as @headfullofbees suggests

https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-leaves-turn-white.htm

 

[Marck]

Greetings, welcome to the Forums.

This does seemlikely be an nutrient deficiency that has progressed to an exceptional level.
An aquaponic-grown plant is in an environment where all nutrients must be intentionally supplied by the grower.
If some nutrient was overlooked or improperly applied, then an nutrient deficiency would be quite likely.

It would be good if the OP included an explanation of which types of fertilizer and application methods had been applied.
That the new grow looks healthy suggests that corrective dosing of fertilizer may have already been applied, though this is also not stated. A Magnesium deficiency can appear somewhat similar on Tomatoes (Solanum lycopersicum), but so can other deficiencies such as Potassium, Zinc, and Chlorine.