Hard water may indeed be the problem.

I have been using TF-4 with no problems of any kind. I dilute it with boiled deionized water and filter the working solution through a paper coffee filter to remove any particulates.

I wash roll film in an annular flow (very low flow rate) washer. I wash sheet film in a tray with multiple water changes. For all washing I use deionized water ("out-of-the-tap" not boiled) because I have it available in my lab (the filtration system removes any particulates larger than 0.02 microns).

At completion of washing I add a couple drops of Edwal Anti-Foam wetting agent to the water. My negs dry water mark and spot free.