i recently started to use TF-4 fix and am pleased with the longevity and speed with which it clears. But i have some problems. I follow my usual washing technique (ie roughly following ilford ecological guidance by filling the tank with water 8 times, each has 1 min agitation then left for three to stand) and always give a final soak in very mild ilfotol solution. I find that all my reels, tanks etc and negatives have a powdery feel tot hem after drying and the negs are heavily marked with water marks. this only seems to have started since i have been using tf-4 and never occured with ilford rapid fix. any thoughts?