I buy 5 liter jugs of fix for minilabs, and I dilute it 1 +4 for both film and paper. It works very well, and it's cheap! Yes, it's nothing more than rapid fix. As far as I can tell, it's equivalent to Kodak rapid fix without the sulfuric acid added. For FB prints I use a two bath system, with 1 minute in each bath. For film, it depends. I usually fix T-grain films for 7 minutes with continuous agitation.