I learned to keep a Tupperware (or similar) container full of distilled water. After a batch of negatives is washed in water, I put a capful of isopropyl alcohol and 1 drop of Photo Flo in the water, stir, and rinse the negs before hanging to dry. No water spots, few dust spots as long as I get out of the darkroom and let the film dry. I reuse the same water over and over again, adding new alcohol and Photo Flo each time. The alcohol helps the water evaporate from the film more quickly, and I think also keeps mutant life forms from growing in the Photo-Flo enriched water.