Quote Originally Posted by timor View Post
Total overkill, unless you live in country with real dirty water supply. I don't think so.
I use for everything tap water; developing, fixing, washing. I have no idea where from in tap water such a large, hard particles could be found, but I think it is a bad idea to wash the film in running tap water.

Seriously, in my case it was gung in the tap water. And it is a pretty common occurence. Infrastructure and water quality varies dramatically from one location to another. Search for some recent posts about water quality. You'll find some amazing posts out there
In my case, my son did a science project analyzing our water supply for particular matter. It was a real eye-opener. That is when I bought a water filter a and a temp regulator. No more spots on my films. Or at least way less than before. I still get occasional spots when I coat my own emulsion and forget to use distilled water for soaking paper.


P.S. I also use tap water for mixing chemicals/washes, etc. I just use filtered tap water.