Hydroponics: Blight or Nutrient Burn?

I have a couple issues on a few of my leaves on my patio tomato. It looks like nutrient burn, but it also looks like it could be blight. Everything I've read said that blight is usually spread by rain/wind. Since my greenhouse is somewhat protected from these elements, it shouldn't be blight. I havent gave these plants a good flush in a few weeks, so that might be the case. What do you think?

Damage is more on the inside of the leaf in this pic

Typical Nutrient Burn Symptoms - Burnt Tips

  

Update: I've gotten a couple responses on a forum I contribute to and it seems this isn't Blight. Blight should have distinct outer rings on the edges and CAN turn the whole branch yellow, very fast.

I will give it a good flush with 5.5ph water @ a 0.0 EC this weekend. I will measure the water than drains through until it is also at an EC of 0. I will write a post on the flushing process and record the improvements. Im also going to use Ubiogrow on the plant to see if this helps also.