Hanna alk reagant difference

[shadyraro]

So I ordered a new alk reagant and got a different part number, HI772S is what I’ve been using and HI755S is what I got.
I tested both in different tubes at the same time using different syringes, filled both with 10ml tank water and both tubes were clean. I put the tubes in the tester the same way as I have a mark to line up, and the differences in results was quite surprising. HI755S read 8.0 dkh, and HI772S read 8.8 dkh. What’s going on?
I started dosing alk a couple weeks ago because it was low according to my results, but now I’m wondering what to believe with these different reagant results. From what I’ve read the reagents are supposed to be exactly the same with one for dkh and the other ppm, but I’m a bit sceptical about this now.

 

[Woodyman]

So I ordered a new alk reagant and got a different part number, HI772S is what I’ve been using and HI755S is what I got.
I tested both in different tubes at the same time using different syringes, filled both with 10ml tank water and both tubes were clean. I put the tubes in the tester the same way as I have a mark to line up, and the differences in results was quite surprising. HI755S read 8.0 dkh, and HI772S read 8.8 dkh. What’s going on?
I started dosing alk a couple weeks ago because it was low according to my results, but now I’m wondering what to believe with these different reagant results. From what I’ve read the reagents are supposed to be exactly the same with one for dkh and the other ppm, but I’m a bit sceptical about this now.

How old is your old bottle, and where did you store it?

 

[shadyraro]

How old is your old bottle, and where did you store it?

The old bottle was probably 2 months old, stored in the Hanna case in a cupboard.

 

[shadyraro]

I just tested using salifert and it was 8.9.

 

[Woodyman]

The old bottle was probably 2 months old, stored in the Hanna case in a cupboard.

That's not particularly old, but you may want to change your storage. When I first got my meter I ran into a similar problem as you, I think that first bottle lasted me 3/4 months though before I bought another. Checked both and had a significant difference like you experienced. Double checked with salifert and the new alk reagent was correct. Then I found the thread below and I've kept mine in the fridge since. Haven't experienced that same issue again.

Thread 'Important findings according how to store open bottles of the reagent for Hanna Marine alkalinity checkers' https://www.reef2reef.com/threads/i...-for-hanna-marine-alkalinity-checkers.893762/



Do you have another way to verify your alk measurement?

 

[Woodyman]

I just tested using salifert and it was 8.9.

Wonder what is up with the new number in that case. Odd, I haven't needed to order recently so I still have the 772S..

 

[Woodyman]

You were sent the wrong reagent it seems.. At least if you have the HC - HI772 checker.

Marine Alkalinity Checker® HC Reagents (25 Tests) - HI755-26

The HI755-26 are the replacement reagents for the Marine Alkalinity Checker® HC - HI755 and Marine Alkalinity (dKH) Checker® HC - HI772.

www.hannainst.com

Marine Alkalinity Checker® HC Reagents (25 Tests) - HI772-26

The HI772-26 are the replacement reagents for the Marine Alkalinity (dKH) Checker® HC - HI772.

www.hannainst.com

 

[Doogs]

I store mine in the fridge. I also noticed the amount of water in each isn’t exactly the same in each cuvette so that might be messing with it

 

[shadyraro]

You were sent the wrong reagent it seems.. At least if you have the HC - HI772 checker.

Marine Alkalinity Checker® HC Reagents (25 Tests) - HI755-26

The HI755-26 are the replacement reagents for the Marine Alkalinity Checker® HC - HI755 and Marine Alkalinity (dKH) Checker® HC - HI772.

www.hannainst.com

Marine Alkalinity Checker® HC Reagents (25 Tests) - HI772-26

The HI772-26 are the replacement reagents for the Marine Alkalinity (dKH) Checker® HC - HI772.

www.hannainst.com

Apparently they’re the exact same reagant, and in this video he says 772 reagant can be used in both dkh and ppm checkers but doesn’t say 755 can.

 

[shadyraro]

I store mine in the fridge. I also noticed the amount of water in each isn’t exactly the same in each cuvette so that might be messing with it

I used a 10ml syringe for both

 

[Doogs]

I used a 10ml syringe for both

Maybe it’s the angle of the photo?

 

[shadyraro]

Maybe it’s the angle of the photo?

Yeah I think so

 

[Woodyman]

Apparently they’re the exact same reagant, and in this video he says 772 reagant can be used in both dkh and ppm checkers but doesn’t say 755 can.

Interesting. Wonder why Hanna wouldn't mention that on their site and/or consolidate part numbers to just have a single refill.

I imagine there has to be some difference in makeup, but who knows manufacturers do goofy things sometimes, and I could see this going either way.

 

[Chris Nano Reef]

According to Hanna site looks like 755 is for the marine alk ppm checker 772 is for the marine alk dkh tester. I see the video you posted but if it were me I would t trust the reading of the 755

 

[Woodyman]

According to Hanna site looks like 755 is for the marine alk ppm checker 772 is for the marine alk dkh tester. I see the video you posted but if it were me I would t trust the reading of the 755

My guess from the site would be they reagents are probably different concentrations in order to optimize the reaction for the given ranges of each meter.

 

[shadyraro]

According to Hanna site looks like 755 is for the marine alk ppm checker 772 is for the marine alk dkh tester. I see the video you posted but if it were me I would t trust the reading of the 755

I have the HI772 checker and believe using the 772 reagant is the correct reading.

 

[gbroadbridge]

You were sent the wrong reagent it seems.. At least if you have the HC - HI772 checker.

Marine Alkalinity Checker® HC Reagents (25 Tests) - HI755-26

The HI755-26 are the replacement reagents for the Marine Alkalinity Checker® HC - HI755 and Marine Alkalinity (dKH) Checker® HC - HI772.

www.hannainst.com

Marine Alkalinity Checker® HC Reagents (25 Tests) - HI772-26

The HI772-26 are the replacement reagents for the Marine Alkalinity (dKH) Checker® HC - HI772.

www.hannainst.com

The reagent is the same, only the part number is different.

The difference is probably because the old bottled was not refrigerated.

 

[Chris Nano Reef]

I have the HI772 checker and believe using the 772 reagant is the correct reading.

I agree since you also double checked with a different brand test and got 8.9 we spend so much time and money on our tanks I would not feel comfortable using the 755 reagent.

 

[gbroadbridge]

I agree since you also double checked with a different brand test and got 8.9 we spend so much time and money on our tanks I would not feel comfortable using the 755 reagent.

Read post #7 in this thread.

New Reagent Code for the HI772 dKH Alkalinity Checker

Hi all, 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...

www.reef2reef.com

 

[Chris Nano Reef]

Read post #7 in this thread.

New Reagent Code for the HI772 dKH Alkalinity Checker

Hi all, 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...

www.reef2reef.com

That’s very interesting thanks for the link. Well according to Hanna they are the same. Still doesn’t feel right if it were me lol. I can understand the OP concern. Especially since the salifert test was 8.9