Question: Testing PH and Distilled Water

[manderkeeper]

I purchased some 6in1 easy strips (tetra). I wanted to do some tests of spring vs. tap water. However, I purchased a bottle of distilled water for testing if the strips were accurate. It says my distilled water is acidic (according to the scale, it hit 6.2 as low as it will go). I had hoped distilled water from Walmart would be very close to neutral, so I am left wondering if the test strips do not work or if the distilled water isn't really neutral. Anyone have experience in this regard?

 

[LSuzuki]

The problem with pure distilled water is that there is nothing to buffer pH changes. So, when, say, CO2 from the atmosphere dissolves in it (forming carbonic acid), the pH drops. (CO2 is extremely water soluble.)

Also, test strips are not usually recommended for accurate tests. The liquid test kits are usually better, and cheaper in the long run.