[Aquattro]

Originally Posted by rayjay

Without any buffering salts in the water you won't get a proper pH reading.
http://reefkeeping.com/issues/2005-05/rhf/index.php#8

Yes, you would. Pure water has a pH and is measurable. Acids are measurable. alkalis are measurable. All accurately, regardless of salts or lack of.

Anyway, not going to argue about it, the question wasn't about measuring pH. It's about does he need to buy a thingy? No, he does not.