Tomato's bottom leaves wilded and dry

[GpsFrontier]

Hello jhinkle,
I have a few questions:

1. How often do you change your nutrient solution?
2. How much nutrient does JRPeters recommend using for a full strength nutrient? I believe they go by weight (something like 11.4 oz) per 100 gallons. They do for the herb formula anyway.
3. How much are you using?
4. What is the humidity?
5. Do the white spots feel powdery?
6. Can you smear the white spots?
7. Do you notice any insects around the plants? Especially like tiny white fly's, spider mites, or aphids etc..

P.S.
I would pluck off the leaves with the white spots. Also I would put them in an air tight bag or burn them to get rid of them.