Strangly when I did my Prochem courses they were so blatently set up as a two day sales pitch I could't bring myself to buy anything or even try any of their chems. It proved to be foolish in the extreme. I have now tried most things, but have gone full circle and now apart from one or two items that I reckon other companies do better ( HM gel being one of them ), I now use nothing other than Prochem chems. Still a few that I want to try, and will. Wouldn't hesitate to change chems if I find somethng better.