Just be aware that the Photo-flo 600 uses a relatively toxic chemical in it that the other Photo-flo solutions do not have. Just avoid touching it, dripping it around the darkroom, etc.
BTW -- here at the university, I am working on a gallon of Photo-flo 2100. I use 7 ounces to make a gallon of stock solution, then use the stock solution at one ounce to a gallon of water! (it does not have the toxic chemical that the 600 has).
