IS THIS SIGNIFICANT?

[Mmathis]

Back when I kept aquarium fish, I recall that I did this as my routine for testing water: After each test, I rinsed the tubes with tap water and let them dry. Prior to performing each test, I rinsed the tubes with fresh aquarium water. The idea being that there would be "chemicals" in the tube left over from the tap water rinse that could skew the results.

Or can I go straight from tap-water-dried, to pond-water-testing?

 

[crsublette]

Supposedly, simple touching the test tube lip or insde of the cap with your fingers will cause a slight pH change ... I have no idea so I am going to stay on the side of caution.

I rinse my test tubes and caps a couple times under the sink. Then, put some di-RO water or distilled water in the tube, cap on, shake it for a couple seconds. Empty it. Then let it sit empty until I need to use it.

Prior to testing, I rinse the test tubes with pond water then get my 5ml of water to test.

I have no idea. I have been wondering the same. I figure ... does not hurt to be too cautious in instance.

 

[buckry]

I do the same thing. Rinse in pond water before test, tap water after test.

 

[fishin4cars]

99 out of 100 you probably wouldn't see a difference. But there is always that chance that tap could contain a residue that could effect some readings. It's best to rinse the chemicals out of the tube with tap/RO or just pond water that will be thrown away afterwards. then prior to testing rinse again with pond water. This will give you the most accurate results. Most of us use drop or strip tests that aren't 100% accurate 100% of the time anyway. They are usually close enough in most case to give us the general information we need. Getting a false reading makes it far more difficult to correct problems. IMO, a minute to rinse with pond water is just a little more ease of mind that the reading your taking is the most accurate possible.

 

[Mmathis]

I was just curious. It's been years, but old habits stay with you -- when I started testing the pond a few weeks ago, found myself automatically pre-rinsing the tubes in pond water. I'm sure I learned that somewhere in the past, probably in instructions with a test kit.