You can get by with using distilled water for the final rinse for reducing spots with film, but a wetting a agent almost guarantees spot free drying. I've been using Edwal LFN for years with nearly perfect results. My formula for final rinse is: 500ml distilled water, one (1) drop LFN, one capfull of 91%isopropyl alcohol. This is reusable and lasts for several months. LFN is also usefull if you have any problems with developer foaming, and reduces bubbles by adding one drop to the dev.