Removing the primers before you wet tumble does more than clean your primer pockets. It allows a better flow of the solution through the brass, it also allows the solution to leave the brass after removing the brass from the solution, helping with drying. I see that system doesn't use pins but if using SS pins in bottle neck cartridges, if you don't de-prime your going to have a hell of a time getting the pins out. I also see several people who left the primers in and didn't remove them in a timely fashion afterwards report the primers were stuck tight into the brass. I usually use a universal depriming die first then wet tumble my brass.
Your solution is just a phosphate based dish detergent & water with approx. ph-4.
https://www.brownells.com/userdocs/M...73_default.pdf
A 10lb tub of powdered phosphate detergent like Bright and Fresh Dishwasher Detergent would make a lot of that solution for $45
Many guys are just using citric acid with a squirt of Dawn or car wash soap with wax. Citric acid is about $32 10lbs
What ever you use be sure to rinse the brass well afterwards.