i use the hydro too. i get the cal/nit off amazon, lot cheaper. no epsom needed with my tap water. i use half gallon jug n put 300grams hydro in 1 and 200g in the other then mix equal parts to mix my nutes.
What's interesting to me is some bigger growers I talk to have rejected the cannabis nutrient hype of liquid nutes and are using powdered nutes (either Jacks or other bulk powders) and they don't change their nute balance, it is one ratio straight through. They often tell me we are wasting out money on the nute hype thing. I am running jacks now and so far its performing great but sometimes its hard to tell a difference because each run is a little different and my skill improves a little each time.