Problem. Differences in -1 dkh

Hello it's work 1 week good, now in KH director - 5.9 dkh, Salifert - 6.7, Hanna 6.9.
I recalibrate pump 5 time and 3 time calibrate PH, KH director same 5.8 - 5.9, same problem differences in -1 dx.
I try change Water value - same. now 50ml water and 16 reagent.
What can i do? I try many time fix it but nothing.

If your KHD measurements are consistently around 5.9dkH, I would trust those readings more than the other kits.

Hanna tests have the tendency to read higher values in general. That is why it shows higher than both the KHD and Salifert kit. Keep in mind also that the KHD performs tests using laboratory standards. A more comparable lab-grade test kit to compare to would be ones made by LaMotte.

With traditional hobby-grade test kits, other variables must be considered. Some which are more susceptible to human-error.
For example:

• Water sample collected: Some folks under or over estimate their water sample size which results in skewed test results.
• Personal perception of liquid "color change": What is considered the ending-color change to one person, may not be interpreted the same by another. An extra drop more may be added and that alters the test result.

KHD minimizes these possibilities of human-error by using pumps which can precisely measure-out consistent water sample size and reagent added. With the KHD, provided the pump has been properly calibrated, if you want to use an 80ml water sample, the KHD will use an 80ml sample every time. Whereas traditional kits rely on our eyes to notice a full color change, the KHD registers the ALK reading with a pH probe. The probe alone is going to be more accurate at reading the correct KH value than relying on our eyes to notice when a full color change has occurred.

One must also consider that the degree of KHD accuracy will depend heavily on correct pump calibration, probe calibration, water sample size, correctly measured sample tube and reagent tube length. The KHD measurement accuracy is +/- 0.1dkH - 0.2dkH; all depending on calibration results and water sample size.

Nonetheless, if you strongly feel the other test results are more credible than the KHD, you have the option to adjust the measurement end-results in the KHD settings page.

Quote:

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Originally Posted by Vinny

If your KHD measurements are consistently around 5.9dkH, I would trust those readings more than the other kits.

Hanna tests have the tendency to read higher values in general. That is why it shows higher than both the KHD and Salifert kit. Keep in mind also that the KHD performs tests using laboratory standards. A more comparable lab-grade test kit to compare to would be ones made by LaMotte.

With traditional hobby-grade test kits, other variables must be considered. Some which are more susceptible to human-error.
For example:

• Water sample collected: Some folks under or over estimate their water sample size which results in skewed test results.
• Personal perception of liquid "color change": What is considered the ending-color change to one person, may not be interpreted the same by another. An extra drop more may be added and that alters the test result.

KHD minimizes these possibilities of human-error by using pumps which can precisely measure-out consistent water sample size and reagent added. With the KHD, provided the pump has been properly calibrated, if you want to use an 80ml water sample, the KHD will use an 80ml sample every time. Whereas traditional kits rely on our eyes to notice a full color change, the KHD registers the ALK reading with a pH probe. The probe alone is going to be more accurate at reading the correct KH value than relying on our eyes to notice when a full color change has occurred.

One must also consider that the degree of KHD accuracy will depend heavily on correct pump calibration, probe calibration, water sample size, correctly measured sample tube and reagent tube length. The KHD measurement accuracy is +/- 0.1dkH - 0.2dkH; all depending on calibration results and water sample size.

Nonetheless, if you strongly feel the other test results are more credible than the KHD, you have the option to adjust the measurement end-results in the KHD settings page.

---

I have calibration kit hanna for check tester- tester show me 5.0 same kit
Now hanna 7.0
KH Director - 5.8
and i don't know how check KH director? difference -1.2 dKH

I would also recommend the lamotte alkalinity test as a confirmation of the kh director readings. My hanna read .6 to 1 dkh higher, when I got the lamotte test it was actually a little lower than the kh director, but just by .1 to .2dkh. I've since stoped using my hanna and have trusted the kh director with lamotte confirmation for the past 2 months. I've had excellent results and the kh director controls my 2 part dosing very well. It's was hard to make the adjustment after believing the hanna for years, but now that I have, I am very satisfied with the result.

Today i send water sample to check in Fauna Marin lab. Business test

may be you can give me link for LaMotte test? thx

It's for 50 tests and there is a refill option. I purchased mine here...
https://www.bulkreefsupply.com/alkal...t-lamotte.html

Not sure outside of U.S. maybe someone else knows if you need

Quote:

---

Originally Posted by Vinny

If your KHD measurements are consistently around 5.9dkH, I would trust those readings more than the other kits.

Hanna tests have the tendency to read higher values in general. That is why it shows higher than both the KHD and Salifert kit. Keep in mind also that the KHD performs tests using laboratory standards. A more comparable lab-grade test kit to compare to would be ones made by LaMotte.

With traditional hobby-grade test kits, other variables must be considered. Some which are more susceptible to human-error.
For example:

• Water sample collected: Some folks under or over estimate their water sample size which results in skewed test results.
• Personal perception of liquid "color change": What is considered the ending-color change to one person, may not be interpreted the same by another. An extra drop more may be added and that alters the test result.

KHD minimizes these possibilities of human-error by using pumps which can precisely measure-out consistent water sample size and reagent added. With the KHD, provided the pump has been properly calibrated, if you want to use an 80ml water sample, the KHD will use an 80ml sample every time. Whereas traditional kits rely on our eyes to notice a full color change, the KHD registers the ALK reading with a pH probe. The probe alone is going to be more accurate at reading the correct KH value than relying on our eyes to notice when a full color change has occurred.

One must also consider that the degree of KHD accuracy will depend heavily on correct pump calibration, probe calibration, water sample size, correctly measured sample tube and reagent tube length. The KHD measurement accuracy is +/- 0.1dkH - 0.2dkH; all depending on calibration results and water sample size.

Nonetheless, if you strongly feel the other test results are more credible than the KHD, you have the option to adjust the measurement end-results in the KHD settings page.

---

today 8.6 KH director, hanna - 8.4
I send analysis in Fauna Marine.

Thanks for the info. Will try to get the lamotte test kit also. currently using hanna and salifert. when my KH readings change, they trend downward. I recalibrate the pumps and the probe. I have played around a little on sensitivity of pump calibrated values and it seems the reagent calibration is the most sensitive. Has anyone else tried this? Also curious if kh measurement sensitive to the tube length measurement tolerance.