I haven't/can't prove/disprove anything, but a target level of 30ppm seems to work well for me. Its slightly higher than what EI calls for according to my dealings with the fertilator.
That's 30ppm per week target. The EI dosages for the 60-80gal. and the fertilator set at 75gal tank=26.7ppm per week. I find a bit more helpful. That's on multiple setups, over the long-term. Even then, some plants seem to want more....that's been my experience.30 ppm???? That is alot.