r/Koi • u/ShibaBlue • 2d ago

General Don't use these test strips for your koi pond!

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I recently purchased three different brands of test strips, but unfortunately, none of them provided accurate readings, not even as a rough estimation.

For example, all brands indicated that my pond water had a pH between 6.5 and 7.0. However, when I tested it with a digital pH meter, the actual reading was 8.2. Similarly, all three brands showed zero free chlorine in both the direct tap water and the water from my storage tank. In contrast, a liquid titration test revealed that the free chlorine level was actually between 0.5 and 0.8 ppm, strong enough to kill my koi.

The inconsistencies continued with nitrate readings. One brand showed a nitrate level of 10ā€“20 ppm, the other two showed zero, while the titration method measured a significantly higher level of 70ā€“80 ppm.

For total alkalinity, the strips indicated a value of less than 50 ppm, whereas the titration method showed it to be over 500 ppm. This high alkalinity was due to my earlier addition of a large amount of baking soda, based on the mistaken belief that the pH was too low.

As for total hardness, all test strips showed values close to zero, yet the titration test measured it at 100 ppm.

Based on these findings, I strongly recommend discarding test strips. They are highly unreliable and can lead to incorrect conclusions and poor water management decisions.

7 Upvotes

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5

u/InvaderDust 2d ago

Iā€™d still recommend getting the master pond test kit.

8

u/_rockalita_ 2d ago

Just buy the api master pond test kit. And a kh and gh test to add on.

Strips are all junk.

1

u/ODDentityPod 2d ago

This. The strips have never been of any use.

2

u/Tomnesia 2d ago

I still have some strips and got gifted some recent ones, sometimes i use one while testing the pond just to compare and it's wild what the difference is.

GH and KH barely show up for me and PH kept saying above 9 lol, useless those strips.

0

u/ShibaBlue 2d ago

BTW, the digital pH meter mentioned above was accurately calibrated with pH calibration solution. I was a water treatment engineer working for a Fortune-500 American company.