Alk test not reliable - hanna checker

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FishyFishFish

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Can I confirm that the ‘standards’ simply test the colorimeter?

Can it be calibrated with the standard or does it just tell you whether the colorimeter is working correctly?

Annoyingly the standard for the dkh Alk checker is more expensive than the others. I wonder if there’s a technical reason for that or just due to demand.
 
Zoanthids

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Can I confirm that the ‘standards’ simply test the colorimeter?

Can it be calibrated with the standard or does it just tell you whether the colorimeter is working correctly?

Annoyingly the standard for the dkh Alk checker is more expensive than the others. I wonder if there’s a technical reason for that or just due to demand.
The standard just checks the colorimeter. You can't calibrate it.
 

truepercs

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I am not sure I am happy with the Hanna checker. After several years using the Salifert I changed as I thought it may be better to rely on something other than my eyesight as I know it is changing. First time using I was happy that it was so easy... Until I bought a new bottle of reagent. I thought I was in my target range however the new reagent tested upwards of 10.

After reading the forum I find that the reagent can easily contaminate. So I modified my test procedure, and carefully watch not to do anything to contaminate the reagent... Now that I am again @ target range I opened another bottle and have carefully tested for the last few days. The readings are consistent with each bottle but the first bottle checks @7.3 and the recent bottle checks @ 8.2 Either my process is still not good enough and I screwed up the reagent again or the reagent just is not consistent from bottles. I am not sure that I am happy with this checker.

I guess an individual would not notice unless they were checking a sightly used bottle against a new bottle. I only use the syringe that came with the bottle, I rinse the tip, air out and let dry before using again. Withdraw reagent and immediately close bottle for the next test. I may stop rinsing the tip all together as my test results suggest that something is still weakening the reagent?
 

Uncle99

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Test can vary if:
There are bubbles in the test solution.
The glass is smugged
The tip on the regent is not fully on.
I found it helpful to pull more than 1ml, then push down to 1ml.
I have never rinsed the applicator, but of course, super clean the vials.
The more I tested, the more consistent my results.
After 3 years, a few times I got a couple of “weird” results but bottle to bottle within 10ppm for me.
Same with the Phosphorus UL and Nitrate HR (High Range) checkers. Top of the class IMO.
 
BRS

FishyFishFish

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It appears that my results stabilised as soon as I stopped cleaning the applicator. I am also now marking off how many tests I do, on the bottle, so it will be interesting to see if the results deteriorate as the bottle is used up.
 

Acroalan

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In addition to a lot of the tips above that help with consistency I'll offer one I didn't see listed. I picked up a 10ml syringe to use to pull tank water and then fill the test vial that way. I feel this ensures I get an accurate and consistent amount of tank water in the vials. I use the same syringe for phosphate and alk checkers.
 

Reef.

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In addition to a lot of the tips above that help with consistency I'll offer one I didn't see listed. I picked up a 10ml syringe to use to pull tank water and then fill the test vial that way. I feel this ensures I get an accurate and consistent amount of tank water in the vials. I use the same syringe for phosphate and alk checkers.

I found that the case too, using a 10ml syringe seems to go just past the line, maybe they measured the 10ml mark with rodi water, as salt water would be a larger volume than rodi water.
 

Reef.

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I think the only advantage of the Hanna over one of the other tests is the digital display, so ease of reading the results.

The other tests give very acceptable results, Hanna PO4 is a must, not so much the alk checker IMO.
 
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