I have used your complete line for several years (in soil) with great success. I now have decided to try my hand at hydro.
My question is...what EC reading should I have when making 20 quarts of cloning mix. Before adding the "Success Formula" my water is 0.1 @ 0.5 (approx. 50 ppm) and after it is 0.3 @ 0.5 (approx. 150 ppm).
I'am not really sure what "0.1 @ 0.5" and "0.3 @ 0.5" means (perhaps 0.5 is your intended conversion rate EC to PPM, which should really be 500 : 1)...but if you are trying to say that after adding Thrive Alive to your water to prepare a cloning solution your EC goes from 0.1 (approx 50ppm) to 0.3 (approx 150 ppm) you're doing fine.
Thrive Alive and water will make a great solution for you to pre-soak your rooting medium.