I've used Cobbs Powermax, and I have to say, for me, It is one of, neigh, THE the most amazing pre-sprays out there. When it works.
BUT...
For me, no pail was ever the same.
And my last pale, was like a Neapolitan ice-cream (performance wise):
1st layer worked AMAZING, spots would melt away, smelled like pixi-stick heaven... I swear it was like a unicorn farting in my face, loved it.
2nd layer, was like using straight water, Wouldn't budge the easiest of stains...
3rd layer, worked very good (Not as good as the first layer) it was back to working like all the "Good" batches I had bought before.
Couple of notes, It was always mixed with the hottest TM water, NEVER in a Hydroforce, always in a Battery sprayer or Pepsi sprayer.
So that removed the likelihood of a crappy Hydro force not spraying the ratio properly.
I run a large carbon filter, then a softener on my truck, so I have soft chlorine free water, that I check every morning.
I will be buying another pail soon, but I'm going to dump it in an empty 55 gal drum and MIX it real good first.
If it works even HALF has good as my best experience with it, it will still out-clean nearly anything.