I've spent some more time working with the plants this week, and I have a tenative solution for the burned leaves issue...

I think the root cause was the proximity of the 400W HPS (High Pressure Sodium) light bulb.  I had it previously positioned approximately 3 ft. from the top of the plants (only about 12 inches from the tallest plants, the tomatoes).  This lamp generates a lot of heat.  It's amazing, I never really noticed it until I removed the lamp for a while.  Here's a great example:  All the plants are sitting in hydroton (clay pellets).  Normally, the hydroton would be constantly damp, from the continual circulation of the water in the aeroponic system.  I only learned this after removing the 400W system for a few days.  The 400W system generates enough heat that the top layer of hydroton was always dry.

I removed the 400W system for a few days, and ran only on the underpowered 125W compact fluorescent.   I wanted to see if it would stop the leaf burning. I admit that this experiment is far from scientific, as I also added the Mag Pro supplement at the same time.  Regardless, the burning has stopped.

As a more permanent remedy, I've added the extensions back into the lighting frame.  Take a look at the picture below; you'll notice that the frame is much taller than last week.  This makes the light less harsh on the plants, and the heat less intense. 

I don't think that any of the plants suffered irreparable damage.  Regardless, I'm going to limit the cycle of the 400W light for a few weeks.  I'm going to start it around 9 hours a day, and see how we do with it.

Lettuce is tasty. I must report a casualty this week.  #16 is no more. 

Here's this week's overview photo.  The strawberries are finally getting moving.  Finally.

Keeping with my promise of solid record keeping, here's this week's chart: