While both types are interchangeable in the tank, the newer ones (the white ones that don't yellow as much with use) pull apart more easily, feed more easily and have less tendency to bind if you are trying to insert a kinked film or if you have a residual trace of moisture in your reel. I have both types and never use the older ones unless I am really short of dry reels. Also, the newer Super System 4 tanks fill and empty faster than the older tanks - important if you processing multiple films in a process with critical timing eg C41