Hannah Dkh Checker Showing Impossible Results? Or is it?

[Juka087]

Hey guys

so a few weeks ago I purchased a hannah DKH checker. I tested my tank with it the moment I got it, and got a DKH of 7.9. This made perfect sense to me at the time as it had been a week since I had done a water change, and I do have a few corals in the tank. I then measured my batch of instant ocean saltwater. The batch was fresh. I get a 9. Well without dosing anything at all or doing any water changed to the tank. I get a 9.4. After this weeks water change I check the tank again, and I got a 10. I then tested the salt water, and it is still a 9. How the hell. is it possible in anyway. That my tank Alk seems to be rising. It registers above what my fresh saltwater does, and I only do 10-20% water changes. This checker does not seem accurate at all. Within the tank I have 2 mushrooms,a hammer, 2 zoanthids, and a candy cane. I own a nuvo 10. It holds 7.5 Gallons of water. This makes no sense to me. Am I crazy? or this checker just insanely wrong? The only thing I put in the tank is 6-8 drops of brightwell coral amino daily, and 1 ml of vibrant every 2 weeks. I dont think any of that could raise the alk? Does anyone have any ideas as to what should be done? Everytime I test the tank it seems as if the alk has just raised in some mystical way. We went from 7.9 to now 10.4 in a matter of 2 weeks. Impossible.

Any help or thoughts on this matter would be amazing. Thanks guys .

 

[Roy Arena]

Instant ocean usually mixed at 1.026 will give you 10.8 dkh. I don't know what you are trying to maintain but you can do smaller water changes so it will have less of an impact the systems dkh. Are you using a refractometer or hydrometer to make sure your salinity is consistent?

 

[Juka087]

Instant ocean usually mixed at 1.026 will give you 10.8 dkh. I don't know what you are trying to maintain but you can do smaller water changes so it will have less of an impact the systems dkh. Are you using a refractometer or hydrometer to make sure your salinity is consistent?

Refractometer

 

[Waters]

Recently I have come to question my Hannah ALK tester results. The first few bottles of reagents I used it seemed to be spot on (verified with other methods of testing). Now it is reading .4 higher every reading (showing 8.8 when my ALK is 8.4) Again, I verified using other testing methods and water with a confirmed ALK reading. I have done back to back readings and got completely different results. Before anybody asks, I did verify that the tube was clean and all steps were followed correctly. I did read that there is an error margin of .5 on those so maybe that is coming into play? I would also pick up another test kit such as Red Sea and see what that reads.

 

[Gareth elliott]

Any water or contamination possible in the reagent bottle or syringe(always throw out the old one). But the ph of the reagent changing even slightly will throw this test off a lot.

 

[Juka087]

Any water or contamination possible in the reagent bottle or syringe(always throw out the old one). But the ph of the reagent changing even slightly will throw this test off a lot.

I'm starting to think the hannah alk checker is a bad idea.....

 

[Silent]

Make sure you are consistent in testing. Every single drop more or less than previous tests will give a different number.

 

[Juka087]

Make sure you are consistent in testing. Every single drop more or less than previous tests will give a different number.

What about the little pipette that goes on the syringe to measure out the reagant. You are only given one.

 

[Silent]

You could also try the alk calibration kit for it to see if its off. $12 https://www.hannainst.com/hi755-11-marine-alkalinity-checkerr-hc-calibration-set.html

 

[Gareth elliott]

this might help in case its user error. If not might be a reagent issue.

 

[madweazl]

I'll give my tips for consistent results.

When I draw the reagent, I do it quickly and cap the bottle right away to minimize evaporation over time.
I use a syringe to draw the 10ml of sample water because it's nearly impossible to eyeball the water in the cuvette consistently.
I do not rinse the cuvette out with sample water prior the test.
I wipe the cuvette down with a microfiber towel prior to placing it in the checker.
I "index" the "10ml" label facing the same direction each test.
I do rinse and dry the cuvette and the tip with tap water after testing.
I store the cuvette with the cap off.


I'm not sure if my results are public or not but it can be very consistent.

 

[Juka087]

I'll give my tips for consistent results.

When I draw the reagent, I do it quickly and cap the bottle right away to minimize evaporation over time.
I use a syringe to draw the 10ml of sample water because it's nearly impossible to eyeball the water in the cuvette consistently.
I do not rinse the cuvette out with sample water prior the test.
I wipe the cuvette down with a microfiber towel prior to placing it in the checker.
I "index" the "10ml" label facing the same direction each test.
I do rinse and dry the cuvette and the tip with tap water after testing.
I store the cuvette with the cap off.


I'm not sure if my results are public or not but it can be very consistent.

How do you get the one ml of reagent? With disposable 1ml syringes? And what's up with that syringe tip they include?

 

[Silent]

I find it best to store my bottles with distilled water in them. Keeps bottles very clean and clear.

 

[Silent]

The syringe tip is supposed to make it more accurate.

 

[Juka087]

The syringe tip is supposed to make it more accurate.

Do you measure out 1 ml on the syringe itself. Or do you use the entire syringe volume, and the tip holds exactly 1ml. Like is the tip volumetric.

 

[Silent]

Put the tip on and draw plunger back to desired amount (say 1ml mark). Air + liquid will be 1ml of liquid.

 

[mike550]

Do you measure out 1 ml on the syringe itself. Or do you use the entire syringe volume, and the tip holds exactly 1ml. Like is the tip volumetric.

@Juka087 you need to measure out 1 ml with their syringe. It looks like the same syringe used in traditional titration tests. A bit hard to read and it’s tricky because there is an air bubble that’s “supposed” to be in the syringe.

Seriously considering buying a better 1 ml syringe

 

[Juka087]

@Juka087 you need to measure out 1 ml with their syringe. It looks like the same syringe used in traditional titration tests. A bit hard to read and it’s tricky because there is an air bubble that’s “supposed” to be in the syringe.

Seriously considering buying a better 1 ml syringe

Oh this is ****** stupid.

 

[madweazl]

How do you get the one ml of reagent? With disposable 1ml syringes? And what's up with that syringe tip they include?

I use the included 1ml syringe and tip to draw the reagent. Draw until the plunger is at the 1ml; there will be a fairly large air bubble between the reagent and plunger (that is the volume of the tip that is installed on the syringe but you still have 1ml of solution in the syringe).

 

[Juka087]

I use the included 1ml syringe and tip to draw the reagent. Draw until the plunger is at the 1ml; there will be a fairly large air bubble between the reagent and plunger (that is the volume of the tip that is installed on the syringe but you still have 1ml of solution in the syringe).

Maybe I should get a 1ml volumetric pipette with a freaking pipette vaccum.....all to find out the checker is incorrect anyway.