I learned a different way of using wetting agent that has worked well for me: I found a plastic container of a convenient shape. Fill it up with distilled water. Each time I process film add a capful of isopropyl alcohol and a drop of wetting agent. Pop the lid back on, shake it up a bit, take the film off of the reels and run it through 4 or 5 times. Give the film a gentle shake and hang to dry without wiping. Reseal the lid on the container and keep for the next time. I don't pay attention to how old it is or how many films I run through, just dump and replace when the water begins to not look crystal clear. No problems at all with drying marks, particles on the film, or scratches from wiping.