X2 on the next test including a tank flusher unit of some kind (quickie, tornado, whatever). Either a tank flusher, or a flush king unit.
I definitely think that your original test would have been much better, if some kind of flushing had been done with the 3" hose setup (whether that flush was done with a tank rinser, flush king, whatever).
You did a flush afterward with the Sewer Solution, but not with the 3" hose. Its no surprise (and not a fair comparison), that you'd end up with a cleaner tank with the sewer solution and flush afterward vs 3" with no flush.
My bet is that if you do a flush afterward with both approaches, you're going to find the tank gets cleaned, emptied 'bout the same with either approach.
