I agree with this 420% and am confident you'll get to a better result.
Here's the issue I see...
I think it's a "mistake" to try to emulate what Doc is doing in hydro. And I did hydro for 10 years before just starting with Doc's kit a year ago. The primary obstacle is that Doc's entire regimen is based on taking advantage of certain soil bacteria that help accelerate nutrient uptake of the plant. Even the foliars are designed to get the plants to exude substances that kick the soil bacteria into "high gear".
In hydro, you don't have that soil bacteria, so you need to supply the nutrients in a format that's immediately usable/ingestible by the plants.
This, IMHO, is why Doc in some previous posts was encouraging you to focus on the strengths of hydro (
@Doc Bud, please feel free to comment!
) instead of trying to use his methods to achieve high brix without medium that's specifically designed for his formulas.
The question then becomes, how do you increase nutrient uptake in hydro? As you know, you can only up PPM's so far, so you can "lead the plants to water, but you can make them drink", so to speak!
Proper environment, especially temps & RH, will play a big factor. Foliar sprays can also help. I would think chelation would help, too, just not sure how to accomplish it unless you get the nutes in chelated form already.
You can also look at introducing beneficial bacteria into the res, which I was never personally a fan of since I've seen too many horror stories when organics get introduced into a reservoir, so I have no experience with, but here's a good article:
The entire brix crowd is very knowledgeable and are great people to learn from. I just think you need to apply that knowledge in a different way in hydro.