Questions for Evaporust Users

The differing results are puzzling? Like Hemix and 413, i have had great success with Evaporust. Been using a 5 gal. pail for 3 years now and have de rusted many many parts. Just did 4 complete door hinges that i'm sure most guys would have thrown out they were so corroded. 2 days and they are sparkling clean!
As for por 15....Run Forest Run!