It’s personal tolerance. If you get any stinging on first use it needs diluted more. I can personally get away with 1 part BW and 2 parts .9% sterile saline. A 1 to 3 ratio will usually never sting but you’ll need more pumps.
@Paradox Legit source. I use them for sterile vials. But in a hurry, Ill get bac water when running low and can’t source it else where. Currently using a bac water from Farris.
Jano has a fee to put other vendors names on the test if you are the original tester.
My point is you dont trust their tests. its one bottle from a batch of 30,000