Hey this isn't really a hydro question but I grow in a soilless medium and I have a question about my resovior. I have a 13 gal bin to hold RO water. There is an airstone and pump at the bottom. I filled it up today and when i went to grab the hose to fill some jugs I felt it covered in a thin slick layer of something. There are no strange colors or anything, but I don't know what this is and am wondering if it might be the start of bacteria in the water which I wouldn't want to feed myself or my plants.