OK, allow me to clarify a couple of things based on the responses:

I'm not growing in soil; hydroponic ebb/flow (see initial post).

I check the ph of my solution before adding the nutes and again after adding the nutes. Subsequently, I check the reservoir ph everyday to ensure its around the 5.8 range.

Also, plants are growing in 4 inch rockwool, surrounded by hydoton. I seriously doubt 'root bound' is the issue.

Thanks for the tip on the superthrive -- I will not add. As far as the total amount of N shown on the back of the nutrient products, it is as follows:

Pure Blend Pro Bloom --> 2.5% N

Instant Karma --> 0.1% N

I'm unsure if the Bushwacker contains any N since it doesn't disclose the active ingredients.

As the picture indicates, I'm only noticing the downward curl on the new growth and I had previous issue with heat stress last week, so that may have added to the severity of the curl.

Should I just reduce the amount of nutes next reservoir change? Or do I need to flsuh with a product liek Clarex?

All your responses are greatly appreciated!