I like what I see in 2 minutes of looking at promix's lineup.I typically use a 5-6 gallon bucket with a few holes drilled into the base, and Promix. I find it's impossible to overwater it due to the holes and water holding properties of Promix. Any time something gets too acidic, I flush with copious amounts of water, which will drain out the excess within an hour with my setup. Promix seems to be perfect for water holding, but it tends to dry out quickly towards the end, requiring about a gallon/day/plant.
I've been using Promix for over 30 years and never had any problems at all. I will sometimes mix maybe 25% composted manure to it, but aside from general ferts, that's about it. I admit that it does settle after a while (which is where the manure seems to help a little with water holding as well as other nutrients that might not be otherwise available) and I usually have to provide at least a gallon of water a day at the end stages. When finished, the roots are so fully engulfing the medium that it's like a sponge, so sometimes I'll put a shallow pan under the bucket to aid in keeping some extra water available. Everything is indoors. I have tried Metromx and tried to make my own, but Promix seems to work best for my methods and experiences. Hell, I'm still using the same magnetic ballasts that I used when Carter was in office!I like what I see in 2 minutes of looking at promix's lineup.
Have you gone to this brand after using ffof or organics? I like the high porosity. I did my own using coir/perlite/amended soil. It seems to settle when I looked at my last run. I use play sand at the top to combat pests.that may play into it as well.