Hi tylertower, Sounds like you have a few things working against you. Firstly, Have you tried reaching-out to the local JP+/TG Rep who sold you the TG? They should be able to provide you with "local expertise" unique to your specific geographical area. I would definitely start there. And remember, you can always call the helpful folks at TG Customer Support with any questions / comments / concerns:
Tower Garden Customer Support
Phone: 866-235-0414 (Available M-F 8am-5pm CT)
That being said, I spot 2 major issues with your setup (there certainly can be more) - Temperature and Nutrient Solution.
Choose your battles (and your crops) wisely. For example: Lettuce is a cool weather crop. You will encounter challenges when attempting to grow lettuce (and many other crops) in 100°+ F temperatures. Nutrient solution temperature is critical... it should be kept in the 65° to 75° F range. Many TG growers in the warmer climates keep frozen water bottles in the nutrient tub to keep the solution cool. Insulating the tub helps. Using shade cloth helps too. You may find the following article helpful:
Helpful Advice for Gardening in the Heat
I would strongly advise that you crawl before you run. Stick with TG Mineral Blend nutrients. [treading lightly here] There are certainly alternative nutrient solutions you can use in the TG. However, selecting and using alternative nutrient solutions in your growing system requires an advanced understanding of how these formulations work and which are safe to use in your specific growing system (by that I mean you, not some dude at the local hydroponics store). For the record, the nutrient solution you mention is not one I would recommend for use in a recirculating hydroponic system such as a TG.
You may find the following docs helpful when using TG Mineral Blend:
How to Mix TG Nutrients
TG Nutrient Strength Selection
Reach-out to your local JP+/TG Rep for help/advise.
Read and follow all of the guidelines in this doc: