Hello widespreadpanic,
good have you back posting in the forum again. Hope all has gone well (except for this tomato problem of coarse). It looks like the first system you built if I remember correctly.
My first thought when I saw the pics was it looks like a magnesium deficiency. But I have a hard time with that because you have used 2 different
nutrients, from two different manufactures, and both were specifically for tomato's. So I just have a hard time thinking it's
nutrient deficiency for that reason. However I forgot to ask how often you change your nutrient solution, what the size of the reservoir is, and how many plants are in the system/s. If you aren't changing the nutrient solution out regularly (and/or often enough), or if your reservoir is to small to accommodate the amount of plants feeding from it, that could lead to deficiency no mater what brand of nutrients your using. Not enough water volume per plant can also lead to big fluctuations in nutrient concentrations, causing a toxicity one day, then deficiency the next. That consent fluctuation causes all kinds of nutrient problems too (regardless of brand of nutrients used).
But assuming you change your nutrient solution regularly, and have sufficient water volume to feed all your plants. I would guess it's probably more like a root disease, fungal disease (most likely in the root zone), or virus. That's why I was asking what the roots look like. I'm also suspecting that the family of frogs in your nutrient solution may play a part as well. I'm not sure, but I think it's possible they could have spread disease to your plants through the nutrient solution. Either directly, or from pathogens, bacteria, and/or fungus from the frog excrement, or feeding/growing from it.
Viruses can easily be spread through the air, as well as insects/pests. Viruses typically cant infect the plant unless there is damaged tissue (like from insects, cuts, or diseased tissue). The insects themselves can transmit the virus to the plant too. But as far as I know there isn't much you can do about viruses once the plants are infected. About all you can do is take caution to prevent new plants from being infected. Like the burning of infected foliage, or disposing of it sealed bags. Then using resistant varieties in the future. The Tobacco Mosaic Virus does look like it could be a issue, though I haven't read enough to know if it typically affects older foliage first. But I have read that TMV symptoms include various degrees of chlorosis, as well as leaf curling, so I couldn't rule that out yet either.