I've been processing film for well over 50 years. Way back, plastic tanks and reels were not so good. They seemed to inhibit the efficient flow of chemistry though the reel. I had to learn to use stainless due to the jobs I had and got used to them very quickly. Now the design of plastic tanks and reels is much improved and my students all use them. Their film always looks fine. I still use stainless though. it's in my blood.