Type and how much brake fluid for pressure flush - P80 and P2

[hausmeister]

You can of course now buy cheap brake fluid testers, but I don't know how accurate they are. Come to think of it I may have one! If I have and can find it I will try and see what it tells me.

I use one of these cheap testers for a few years now, I think it works good enough to tell when your fluid is going bad. Before I replaced the leaking ABS pump It only lasted 1, maybe 2 years in the 850, after I replaced it it is now much less moisture ingress. Results from the tester mostly matched the yearly inspection results for me.
Important thing is to clean the 2 contacts and to fully submerge them, partway can give a different result.