Checking alkalinity with the Hanna dKH Checker | BRStv How-To

[randyBRS]

Hey guys,

With Ryan on a little summer vacation, we're taking a quick break from BRStv Investigates. Luckily I have a TON of how-to videos ready to go, so today we're getting another quick one!

Today, I'm testing alkalinity with the BRS staff favorite Hanna Checker! Hopefully some tips and tricks I show you today help you get the most accurate results with your checker!

 

[Hanna Instruments]

Hey guys,

With Ryan on a little summer vacation, we're taking a quick break from BRStv Investigates. Luckily I have a TON of how-to videos ready to go, so today we're getting another quick one!

Today, I'm testing alkalinity with the BRS staff favorite Hanna Checker! Hopefully some tips and tricks I show you today help you get the most accurate results with your checker!

Awesome Video,
Check out our blog on 8 Checker best Practices
We updated the reagent product code used for the HI772 dKH Alkalinity Checker. The new code is:

HI772-26 Marine Alkalinity Checker® HC Reagents for HI772 (25 Tests)
http://hannainst.com/marine-alkalinity-checkerr-hc-reagents-25-tests.html

This have been updated from the HI755-26. The chemical used is still the same we just created a new code to match our reagent categorization system. The HI755-26 Alkalinity reagent for the ppm Marine Checker is still an active code and the reagents can be used interchangeably.

Thank you for testing with Hanna Instruments!

 

[foxt]

I have read some debate re: the accuracy of the line on the cuvette. I've been filling mine with 10ml from a syringe, and the water level is almost always quite a bit above the line. I've checked my syringes, and they are accurate. From what I have read, the consensus seems to be that the cuvettes can sometimes be marked incorrectly, and that I am ok with using my 10ml syringe. What do you think?

Also, is there a point at which these cuvettes should be replaced? I've been using mine on a daily basis for a year now, and some of them are getting visibly scratched. I haven't noticed a significance difference in accuracy that I can attribute to the scratches, but it does make me wonder. Do others have experience with this?

 

[Hanna Instruments]

I have read some debate re: the accuracy of the line on the cuvette. I've been filling mine with 10ml from a syringe, and the water level is almost always quite a bit above the line. I've checked my syringes, and they are accurate. From what I have read, the consensus seems to be that the cuvettes can sometimes be marked incorrectly, and that I am ok with using my 10ml syringe. What do you think?

Also, is there a point at which these cuvettes should be replaced? I've been using mine on a daily basis for a year now, and some of them are getting visibly scratched. I haven't noticed a significance difference in accuracy that I can attribute to the scratches, but it does make me wonder. Do others have experience with this?

Thank you for using our products and for taking the time to ask these questions!

Its very unlikely that there are errors in the 10ml line, this is due to the manufacturing process and our strict level of quality control. ( we are an ISO 9001:2008 certified company)
We also regularly validate our Checker cuvette volume with calibrated laboratory pipettes. If you have photos of how far above the line and how you fill your syringes feel free to send them over via direct message.

When filling the cuvette, you need to read the meniscus, in the case of our Checkers it would be a concave meniscus. The bottom of the curve reaches the 10ml line for the cuvette. In addition, you need to read the fill line at eye level on a flat surface. Any deviation in the level of the surface can cause the line to be skewed.

Image credit and source is from Anne Marie Helmenstine, Ph.D.

If you do notice that your cuvettes are somehow not consistent please contact [email protected] or 401-765-7500 Monday-Friday 8:30am to 5pm EST. Also feel free to send us pictures through Reef 2 Reef. We take testing very seriously and will address any problems or issue that may arise.

We recommend replacing any cuvettes with scratches or where visual clarity is compromised. Its hard to quantify to what degree accuracy is affected by scratches, however based on the principles of colorimetry it may cause inadequate or untrue absorption of color by impeding the pathway for light.

We now sell two cuvettes and caps in a set of 2 for only $8.00. you can get them from @Bulk Reef Supply

 

[foxt]

Thanks for the response. I will gather my cuvettes together and do some comparisons between them, and send you photos of the ones that I find to be off.

I had found one of your product videos (I forget where, probably on your website?) which explained the need to fill as in image A. I think the video may also have provided the hint to use a syringe to get an accurate fill, and I have been doing that ever since.

I am glad that you're offering the option of purchasing two bottles and caps now, in addition to the set of four (without caps). The $8 option seems more reasonable, so thanks!

 

[dvbrien]

Every 10ml syringe I have also fills about 1/8th to 3/16 above the cuvette line, in form as shown above... I've used 4 different syringes. Frankly Google searching "Hanna 10ml line not really 10ml" lead me to this post and others. The OP is definitely correct. So do we fill with 10ml or do we fill to the Hanna 10ml line. I've also placed every cuvette side by side and the line is the same on all of them. The Syringes are also, all different manufacturers. I've even used the kids little medicine cup filled it to the 10ml mark and it was over the cuvette line...
Granted all of my cuvettes are from checkers at least 4-5 years old, but still functional. Just wondering what he deal is because there' no way I've been getting accurate readings. Filling to the line to test once and then filling with a true 10ml sample to test twice, to then get an average is a serious pain in the ars and a serious waste of reagents and money. Can I get replacements please?