Reference solutions

[Henry Hatch]

I was thinking about making reference solutions for NO3 and PO4 testing. I found Tom"s instructions for making the solutions and noted that the amounts of KNO3 and KH2PO4 to be used went out to 3 decimals. How accurate a scale do I need to do this and can I get one at a reasonable price ?

Also can I use regular distilled water instead of ro/di ? Does it need to be USP grade ?

Henry

 

[Tom Barr]

LeftC just modified his instructions for 2 decimal places, I would suggest Ebay for a cheap decent scale to 3 places.

Regards,
Tom Barr