I like a higher proportion of nitrate to ammonium to avoid tampering with other efforts to alter pH. I'd have to review the breakdown for ammonium nitrate. My pH hovers in the mid 7's. If you have pH readings in the 8's , however, your acid concentrate may have to be so strong as to shorten the life of your injector equipment. Since ammonium is acid forming in the growing media and root zone, you may therefore consider more of a 50/50 blend. What happens is the processes of nitrification and plant uptake release more H+ ions into solution than the bicarbonate release from plants during uptake of NO3. In other words, it takes more nitrate to counteract the acidifying effects of ammonium.
I prefer to grow with a buffered lightweight blend of loam soil, coir, and pumice, so can't claim much practical experience with hydroponics. I will say a couple more things about ammonium. I opt for less because I've noticed poorer quality growth on succulents in association with its use relative to nitrate. In addition, I don't like the way ammonium volatilizes into ammonia gas, especially during high temperatures and high pH. This gas can actually kill many microorganisms
Urea rapidly hydrolyzes into ammonium and can lead to a burst of ammonia gas. I've killed the roots on some plants with that stuff. I don't see a real need for it. Might as well piss on your plants.
Have you looked into
Grow More products? I'm looking into them now.
Matt