Australia's Science Forum

I was wondering how many of you make the pH solutions up using the tablets, and how many buy the solution already made up? We bought solutions last year, but after only using about 200ml of the 500ml bottle, they are all now out of date.

Always use tablets, for the same reason. Tablets I have, make up 30 ml pH solution way enough for calibration, and really, our students use it once a year. Tablets last much longer.
Lada

Thank you for that information. I will order them today!!