Could that be early blight?

Without knowing enough information about your system, I would venture two guesses about the problem(s) facing the Roma.

First, large plants in DWC (especially if it is a static DWC - one in which the solution is confined to one area (e.g. a bucket or tote) without flowing) can become hypoxic; quite literally, the plants are suffocating because they can't get enough oxygen to their root systems. Hypoxia symptoms include wilting, followed by the development of chlorosis and ultimately necrosis. You said that the wilted leaves exposed to the sun are developing necrosis (i.e. dead/brown spots), which leads me to believe this is the most likely cause. If you haven't already, I would add an airstone(s) to the system; from time to time, you can also add hydrogen peroxide in low doses - this will provide extra oxygen, but it will also kill organic matter (i.e. bad and good bacteria, viruses, and don't forget: plant roots).

Second, it could be a nutrient deficiency. Where did the chlorosis/necrosis begin: young leaves or older leaves? On the leaf margins, or middle? Wilted leaves in combination with chlorosis/necrosis could be a chlorine deficiency or a combination of multiple deficiencies. If your reservoir is small, I would just change out the nutrient completely with a well-balanced solution that is fitting for the plant's stage of growth.

To sum up, the problem likely is insufficient oxygen in the root zone; to correct this, add airstone(s). It might be a good idea to also change the nutrient solution with one that is perfectly balanced.

Just to clarify, Hydrogen peroxide will not destroy your roots. It will kill all the beneficial bacteria though, leaving more room for the bad ones to grow. And you have to keep re-applying it if you want everything to stay dead. This is usually counter productive. I would suggest airstone 100%, it's an issue of oxygen.

Just to reclarify, H2O2 will affect any type of biological growth - including roots. This is a primary reason why growers are cautioned against using highly-concentrated hydrogen peroxide. But I agree with OH that your problem is likely oxygen deprivation.

Just to re-re-clarify H202, the "effect" it has on roots is negligible. If you put 235% straight into it than maybe yes, but if you get the 3% solution from your local drug store and dump it into your 55 gallon drum or water (or whatever size your rez is), than it will be fine as long as it is diluted down. I have used it many times and it never bothered the roots, but I stopped doing that long ago because it's a losing battle. The good bacteria seem less resilient and die off, leaving even more room for bad bacteria to grow back. Then you have to keep applying it every few days also.

If you stay between 500 and 1000 ppm, H2O2 won't hurt a thing.

Help my tomatoes are sick too. This is my first effort at hydroponics. The tomatoes looked fine when they were under about 1ft tall but as they got taller the upper leaves started not developing properly and look quite shriveled. The fruit is small and knotty. They are in an ebb and flow system that contains Grodan rock wool. The water runs 5 times daily between 6 AM - 6 PM. The roots are wet about 15 min each time. The plants were seeded in 4 inch peat pots and there are very few short roots extending below the peat pots now. I expected a larger root system into the rock wool for 20 inch high plants with multiple green tomatoes. There is no air bubbling added to the tank, but as it runs the overflow tubes do a lot of sucking and gurgling. I figure it must be getting some air there. Also the overflow tube is splashing and cascading down the wall of the tank. The pH has been maintained near 6.
It seems that the plants are stressed.

No meter will measure PPM/EC/TDS of H2O2 only.

The original poster's plant is probably dead by now. I don't know about the "maxi" series of nutes, but with the regular bloom and grow, they don't contain micro nutrients. You have to also buy the GH "micro," which is a dark purple in color. Micro also has nitrogen, so I don't think you need the green Grow nutes at all for growing a tomato. Grow would be more suited for lettuce.

As for the pic above me, there's probably something wrong with the root ball. It's rotting, or too hot, or the area is too small. Look up the "water farm" machine and try to build one of those. It circulates the nutrient solution constantly, but in a very low flow. You will end up with huge roots.

could be bacterial spot. if the roots are suspended in water it will have to be aerated. keep the ph in check. the ph will drift upward as the nitrogen is used causing a micro deficiency.

I've got identical looking leaves on my greenhouse plants ( hydro). I've assumed it was early blight and sprayed with 0.017% copper. The condition hasn't spread and the plants are in full production. Take it for what it's worth.
Earl

I have a similar situation to the op. I bought a tomato from Lowes (can I say that) with spots on it. The roots looked nice but the plant looked rough and there was NO smell to the leaves. It has grown 6 inches since I have had it. The new growth is nice. However the old still looks rough and has no smell. Some old leaves have at least one small dry spot usually around the tips.my question is should I remove the old leaves and just stick with the new. Or should I play wait and see. This is my first system that is doing well... Don't want to mess it up to badly.

Looks like Calcium deficiency.

What is the calcium concentration you're using?

It should be 180 - 200 ppm.

Are you replacing some nutrient solution for water?

I am going to agree here with Cole Robbie- said some very good points.

Not sure what constitutes micronutrients, but MaxiGro contains:

10.0% Nitrogen
5.0% available phosphate (P2O5)
14.0% Soluble Potash (K2O)
6.0% Calcium (Ca)
2.0% Magnesium (Mg)
3.0% Sulfur (S)
0.12% Iron (Fe)
0.05% Manganese (Mn)

Seems like it contains micronutrients. If it is enough micronutrients for tomatoes, I don't know. For Lukes problem though it looks like that tomatoe is very stressed. Try doing a reservoir change, spray the roots a bit, get rid of all salts, and then let pure water run in the system for a day or two. I think that will help solve your problem.

If the plant looks less stressed after a day or two then try using a weaker nutrient strength than you're now.

The micronutrients are the Iron and Manganese.

The macronutrients are NPK

The secondary macronutrients-Calcium, Magnesium, and sulfur.

The thing that is best about maxi is look at the secondary nutrients levels, they are very high. Way higher then most liquid fertilizers. Using maxibloom: you should never need to use additional cal/mag. Maxi is missing some basic micronutrients though.

I look at maxigrow and the secondary macronutrients ratio are perfect. Then when you look at maxibloom it has 5% Ca, 3.5% Mg, and 4% sulfur. They adjusted it perfectly for the specific phase of the plants life.

OK thanks for clearing that up.