Hanna a reagents are horrible

[Scdell]

Here's the deal. As I use the test kit and the reagent gets older my alk climbs. I test at least three times a week.
This am I tested and got a 9.0 result. I opened a new reagent and re tested. 7.6. That's a huge difference!!!!
If I need a tester to check my tester, then what good is having it????

 

[dwair]

Yep I stopped using them, went back to Salifert. Least i get consistent testing with them. Hanna, I always get different results if i retest, and they are usually pretty large differences.

 

[Anthony Scholfield]

Never have a problem with them, its typically user error.

 

[Scdell]

Never have a problem with them, its typically user error.

It's a pretty simple procedure. Please explain user error. From one reagent to another there's a 1.4 difference? Might be you need to start checking your results with a more reliable test kit.

 

[piranhaman00]

I am going to say user error as well. Never a problem here. You must wipe that vial clean with RODI water and dry off with lint free wipe (kimwipe). Do not touch the glass after cleaned. Finger prints will cause false readings, the glass must be perfectly clean. After use wash clean with RODI. Replace if needed. I found it also very important to read the cuvuette in the same orientation. ie. place the "10mL" writing toward the cover lock every read. This way any imperfections in the glass or what have you are read the same way each reading.

In your defense when these came out there was a bad batch of reagent going around. Its possible reagent issue but like I said, I never see any issues with mine, but I am extremely meticulous with cleaning them.

 

[Arabyps]

Never had an issue except I think the reagent packets are difficult to pour. The one common issue I have noticed among users (may not be true in your case) is failure to thoroughly clean the vial of ALL finger prints and other blemishes before placing it in the checker. Failure to do so will make the reading meaningless.

 

[Cell]

I daresay this product has been heavily vetted by the industry, both hobbyists and vendors, and the consensus seems to be it's one of the best available.

 

[Bryknicks]

I am going to say user error as well. Never a problem here. You must wipe that vial clean with RODI water and dry off with lint free wipe (kimwipe). Do not touch the glass after cleaned. Finger prints will cause false readings, the glass must be perfectly clean. After use wash clean with RODI. Replace if needed. I found it also very important to read the cuvuette in the same orientation. ie. place the "10mL" writing toward the cover lock every read. This way any imperfections in the glass or what have you are read the same way each reading.

This! I use the alk, cal, and phos Hanna checkers and was getting inconsistent results. I watched a video on making sure to keep the glass clean and oriented the same way each time you use the viles. Since I followed this advice my numbers have been spot on.

Another point to note is that the alk reagent does get impacted by oxygen. It's best to limit the amount of time that the reagent bottle is open. Over time I do think that the reagent can be altered but not to the extent the OP has an issue with. I would have to think testing error as well.

 

[Scdell]

I am going to say user error as well. Never a problem here. You must wipe that vial clean with RODI water and dry off with lint free wipe (kimwipe). Do not touch the glass after cleaned. Finger prints will cause false readings, the glass must be perfectly clean. After use wash clean with RODI. Replace if needed. I found it also very important to read the cuvuette in the same orientation. ie. place the "10mL" writing toward the cover lock every read. This way any imperfections in the glass or what have you are read the same way each reading.

In your defense when these came out there was a bad batch of reagent going around. Its possible reagent issue but like I said, I never see any issues with mine, but I am extremely meticulous with cleaning them.

Feel free to think as you may.
I use alternate the two vials between tests. They get cleaned with rodi after use, I wipe them before I put them in the tester. Nowhere in the directions does it say to index your vials.
If it was a contaminated vial issue it would have read the same 9.0 with the new reagent. The only difference between the tests was the reagent.
I have noticed this for quite awhile now. There's threads on here about the reagent solidifying. It didn't always do this and this is when I've started noticing my Alk climbing as the reagent gets older.
This IS a Hanna issue. Plain and simple.

 

[Cell]

Perhaps your unit is defective. Maybe see if you can borrow someone else's and compare results?

 

[piranhaman00]

Feel free to think as you may.
I use alternate the two vials between tests. They get cleaned with rodi after use, I wipe them before I put them in the tester. Nowhere in the directions does it say to index your vials.
If it was a contaminated vial issue it would have read the same 9.0 with the new reagent. The only difference between the tests was the reagent.
I have noticed this for quite awhile now. There's threads on here about the reagent solidifying. It didn't always do this and this is when I've started noticing my Alk climbing as the reagent gets older.
This IS a Hanna issue. Plain and simple.

Alternating between vials is your first issue. You need to use the same vial every single time. When the vial becomes worn visibly, toss it. You can purchase new vials HERE for cheap without cap, save your caps.

There are a lot of things missing from the directions, that doesn't mean you just dont do them. You must wash out the pipette tip with RODI in between uses. The reagent will stick in the pipette and be re introduced to the next sample.

There are a lot of small tricks with these instruments not in the directions, I think I mentioned most, other people will give their tips hopefully.

You can make a standard solution and check it to verify if that helps, or verify with salifert if you are comfortable with that.

This IS (most likely) a user error and if you would like to figure it out we are here to help!

 

[Fourstars]

Just started using Hanna phosphate checker and cross check it with my Salifert multiple times and spot on. Do you rinse your vials after each use?

 

[William Norman]

Alternating between vials is your first issue. You need to use the same vial every single time. When the vial becomes worn visibly, toss it. You can purchase new vials HERE for cheap without cap, save your caps.

There are a lot of things missing from the directions, that doesn't mean you just dont do them. You must wash out the pipette tip with RODI in between uses. The reagent will stick in the pipette and be re introduced to the next sample.

There are a lot of small tricks with these instruments not in the directions, I think I mentioned most, other people will give their tips hopefully.

You can make a standard solution and check it to verify if that helps, or verify with salifert if you are comfortable with that.

This IS (most likely) a user error and if you would like to figure it out we are here to help!

piranhaman00 - thank you for sharing the link. Never knew about this.
-

 

[infinite0180]

Mine are excellent. I do work in a lab though so maybe im used to working with these types of testing devices more than others...

 

[piranhaman00]

Mine are excellent. I do work in a lab though so maybe im used to working with these types of testing devices more than others...

Same here, Im wondering if some things I do that are common practice for lab work are not as clear for people not in science fields.

 

[amps]

The only time I had problems was when I wasn't consistent or as careful as I thought I was. Now that I have a set process, my results are always dead on.

I use the same vial and cap every time.
Rinse vial with tank water twice.
Fill the vial with a pipette until the bottom of the meniscus is at the top of the white line.
Put the cap on and then use a glasses cleaning cloth to carefully wipe all dirt, oil or fingerprints off.
From then on I only touch the vial using the cloth or by holding the cap.
Tap twice on the counter to release any air bubbles stuck to the glass.
I put it in the tester with the 10ml marking facing the front.
When measuring the reagent, I always make sure that the bottom of the stopper lines up to the top of the 1ml line.
As soon as I finish drawing the reagent, I put the the cap back on the bottle tightly to avoid any tiny evaporation or spills.
Using the cloth to hold the vial, I add the reagent and turn it upside down 4 times to mix it evenly.
Tap twice and then do the C2 test.
When I'm done, I rinse both the cap and the vial with tap water thoroughly and toss em back in the box.

I think the key points are the repeatability in filling to the exact same mark and keeping the vial clean. Since the test is comparative between the C1 and C2 stages, the vial can be imperfectly cleaned and still give accurate readings as long as you don't wipe it or mark it mid-test. Choosing the same fill point on the vial is really important as well. The difference between the bottom of the dash and the top can be as much as 4 drops which is roughly 2%. That changes a reading of 8.4 to 8.6 (8.568 rounded up).

 

[piranhaman00]

The only time I had problems was when I wasn't consistent or as careful as I thought I was. Now that I have a set process, my results are always dead on.

I use the same vial and cap every time.
Rinse vial with tank water twice.
Fill the vial with a pipette until the bottom of the meniscus is at the top of the white line.
Put the cap on and then use a glasses cleaning cloth to carefully wipe all dirt, oil or fingerprints off.
From then on I only touch the vial using the cloth or by holding the cap.
Tap twice on the counter to release any air bubbles stuck to the glass.
I put it in the tester with the 10ml marking facing the front.
When measuring the reagent, I always make sure that the bottom of the stopper lines up to the top of the 1ml line.
As soon as I finish drawing the reagent, I put the the cap back on the bottle tightly to avoid any tiny evaporation or spills.
Using the cloth to hold the vial, I add the reagent and turn it upside down 4 times to mix it evenly.
Tap twice and then do the C2 test.
When I'm done, I rinse both the cap and the vial with tap water thoroughly and toss em back in the box.

I think the key points are the repeatability in filling to the exact same mark and keeping the vial clean. Since the test is comparative between the C1 and C2 stages, the vial can be imperfectly cleaned and still give accurate readings as long as you don't wipe it or mark it mid-test. Choosing the same fill point on the vial is really important as well. The difference between the bottom of the dash and the top can be as much as 4 drops which is roughly 2%. That changes a reading of 8.4 to 8.6 (8.568 rounded up).

Very good points, especially about filling to same point each time!

 

[Potatohead]

How old was the old reagent?

I find sometimes old reagents will read about .2-.3 higher than a new one, it typically takes me about 6-8 weeks to use a bottle. I assume this is due to some slight evaporation changing the concentration of the solution over those few weeks.

 

[Albertan22]

Their bottles are only meant to last 2 months once opened, and are very prone to saltwater contamination. If you are dipping the tip of the syringe into your sample water then doing another test before cleaning you will ruin your reagent. If you aren’t testing frequently and don’t use the bottle up in the allotted time, the values will drift upwards as well.

I have had issues between alk reagent bottles. My procedure is to fill a vial, wipe with lint free cloth, ensure no bubbles, place in device with 10ml marking forward, remove and add reagent ensuring the syringe tip doesn’t touch the sample water, seal, invert 5 times, ensure no bubbles, wipe vial again, place back into device with same orientation, take reading, rinse vial and syringe with RODI and put away.

When I change reagent vials I always run one test with the old reagent and immediately run another test with the new regent. I recently had a 1.4 dkh difference between reagent vials. I contacted Hanna technical support and they told me that there was nothing wrong, that it was within the margin of error for their product. I just noted the difference in value and used it to set a new target alk and used up the bottle of reagent. The next bottle of reagent returned to “normal”.

 

[NeverlosT]

what I do:

When i only have one test left of reagent in the bottle, i test my water.
Then i test again with the new reagent using exact same methods, compare.

They are almost always within 0.3 dkh of each other (error in the system is probably 0.3dkh or 0.4dkh)

If i get a large delta, i may not use that reagent.

I also started storing the vials in rodi water to reduce staining and deposits on them, and definitely wipe them down before and during use.

I love the alk checker, I use it almost daily and have had a few of them. Hanna did have a bad batch of reagents years ago but they replaced all for free.