At 2-3ml/gal, it's hard to believe it's supplying much of anything. Especially $7 worth of anything.
It would be interesting if you did a side-by-side with another foliar product. In the other thread you replied to a post that contained two recipes. (That's why I thought you were referring to a recipe you found here.). Have you thought about trying one of those?
For example, it could be just the water improving humidity around the plant, or creating a temperature drop due to evaporation. Or, stimulating the stomata. Or, if a touch of SuperThrive didn't do something.
I'm skeptical of stuff like this because I could sell 20g of dolmite powder on eBay, call it "Dapper Dust: a blend of proprietary earth dust to make your soil more hospitable for root development. Add just 2g per gallon of soil." I guarantee I'd sell 10 of those for $60 (+ shipping) in 30 days. Before long there would be people on forums saying "this stuff works! I saw it with my own eyes. If it improves my yield by 5% it's worth it!"
I'm with you. I have a cycle end every 30 days. I'm constantly trying different foliar sprays. It's more of a curiosity thing to me. I'll pick a table and spray it with one product. Once in a great - and I mean great - while, I notice a difference.
I used to hump the chemical makeup of things until I realized there are too many variables. My strain may respond to a certain nutrient drastically different than yours. I don't believe in blanket claims so I just try shit with my strain. It's helped me too. For instance, I'd been using clonex for ages, tried new agents constantly, always went back to clonex. Finally hit one that works WAY better for my strain. Like amazingly better. Same major ingredients, wouldn't be able to predict it by looking at the bottle. Just happens to work well with my strain. My friend's strain won't take it at all.
New products all the time, it's a fun game. After hundreds and hundreds of harvests, it keeps it from getting boring as shit.
And about selling the powder, you totally should. That's business. Most products on the market that have made millions are as simple as that.