Kodak Professional Kodafix Fixer (32 oz, to Make 1 gal) can be used with developers from other manufacturers.

The added hardener in this fixer is more than enough.

I will use a mixture twice.... first time for 5 min with one batch of film ( I develop Two rolls at a time) , and then the second time will be in the tank for 7/8 min for the second batch of film. The solution becomes weaker as a Fixer, the second time around , thus You need to keep it in the tank a few minutes longer

Best practices say you should use a stop bath after developing and fixing. You could consider using a monobath developing (basically an all-in-one developer/fix/stop) like this Cinestills Df96. Results may look a little different but it will depend on the results/aesthetic you're trying to attain. See the last link provided below for Cinestills' developing times and more info. https://bhpho.to/3Exg05e https://bhpho.to/3ArKmU5 https://bit.ly/3tUshvr

The Kodak Professional Kodafix Fixer can be used with a water "stop bath" when developing film or printing on RC paper. For fiber base papers, a stop bath is required.

Yes, it is normal for there to be sediment or particles in the Kodak Professional Kodafix Fixer. It should not affect the quality of the product, and should dissolve when you dilute the fixer..

Since the Kodak Professional Kodafix Fixer is sealed, it should be good.

Once stock is mixed, I usually use it straight. You never want any question as to whether or not your film is fixed. As for reuse, just pour it back in the jug. 1 gallon of stock is usually good for 100 rolls of film. I know there are some additives that can indicate when your fixer is spent, but I don't have any experience with these. YMMV. Hope this helps! :)