Hanna vs Red Sea which to believe?
- Thread starter Benhuan
- Start date
- Tagged users None
Waters
"...in perfect isolation, here behind my wall."
I am willing to bet, if you test again with the Hanna back to back, you will get a different reading. I have never tested twice and got the same result. Sometimes the changes are within the allowable range...sometimes not. Every test is done exactly the same way.
chipmunkofdoom2
Always Making Something
Without having a reference solution to test with both and see how far off the result is, there's no way to know for sure which one is "correct" or "more right."
What were your last results? How have your phosphates been trending?
What were your last results? How have your phosphates been trending?
DeniableArc
Well-Known Member
- Joined
- Nov 19, 2019
- Messages
- 645
- Reaction score
- 963
- Location
- Sydney
- What state or country do you live in
- Australia
I have had nothing but problems with Red Sea p04 test kit with icp test to back up the false/high results. Hanna ultra low phosphorous checker is very consistent and very close to icp test.
- Joined
- Sep 21, 2018
- Messages
- 7,571
- Reaction score
- 7,962
You don’t mention which Hanna Checker model you are using. Let’s assume it is the LR version with a 95% confidence interval 0.04 ppm (the ULR version has a smaller interval). When you observe 0.11 ppm, the true value is between 0.07 and 0.15 ppm. The Red Sea has no published 95% confidence interval because each user adds an unknown amount of variability to the measurement. For discussion purposes, let’s assume it is the same as the Checker’s (In reality it is much larger) which means the true value is between 0 and 0.08 ppm. For your single observation, we are not justified calling the two measurements different.
The answer to your question: rely on the test with the smaller 95% confidence interval, the Hanna Checker.
