Hanna checker: Why different cuvettes for cal and test?

[kwajtrader]

I'm sure I'm missing something obvious here, but why wouldn't you use the same vile to calibrate the checker as you would to run the test? Doesn't calibrating with one vile and then adding reagent to a different vile add an unnecessary variable?

 

[bcavalli]

Are you using the calibration kit? It comes with two vials. You never open or reuse the calibration vials.

 

[kwajtrader]

No, the instructions say fill one vile with sample water, insert it and zero the unit, then fill the second vile with sample water and reagent to take the measurement.

 

[bcavalli]

I gotcha. I always use a vial with sample water and add the regent to that vial. There isn't a need to use two different vials.

I believe they give you two for calcium (one extra vial) and one with the alk kit.

 

[kwajtrader]

That's what I did too, but the instructions and video from BRSTV specifically use two separate viles. There must be some reason.

 

[lakin58]

I had the same question a few years ago. Tried it both ways. Using 1 bottle and adding reagent and using 2 did them right after each other.

The readings were within the margin of error. So, I used 1 ever since.

 

[bcavalli]

Wow somehow I missed that video. Lol.

 

[zachxlutz]

I wondered the same thing after seeing the BRS video. I fill up one cuvette with tank water,wipe it down and take the first baseline reading, add the reagent to the same cuvette, flip it 5 times, wipe the cuvette down once again and take a reading. It works fine for me with this method.

 

[voodoojar]

some tests like Phosphorus take longer to complete than the tool stays on. So to do it correctly you need to use two vials.

 

[kwajtrader]

voodoojar;1102407 wrote: some tests like Phosphorus take longer to complete than the tool stays on. So to do it correctly you need to use two vials.

I'm not sure I understand since you only put the reagent in one vial regardless of if you use one or two vials. In the case of two vials you put the reagent in the second vial.

I sent this same question to BRS last night. I'll let you all know what they say.

 

[voodoojar]

For phosphorus you put C1 in and press the button then you take it out and add the reagent and shake for 2 minutes and put it back but if you're not quick about it the tool auto shuts off. so having two vials makes it so that doesnt happen.

 

[bcavalli]

I had that problem with the phosphate checker. It would shutoff before I could finish the test.

 

[zachxlutz]

Ahhhh... this makes sense. I only use the Hannah Alk dKH checker. takes all of 3 minutes to do the test. I wish all of our tests were that simple!

 

[bcavalli]

No kidding.

 

[kwajtrader]

Okay, the experts from BRS have spoken: You can do the test with just one vial, but as voodoojar pointed out, the second vial let's you move more quickly.

Mystery solved!

 

[bcavalli]

Great job. Atleast we have an answer.

 

[Trizzino]

If you hold the button down when you are on C2 test vial it starts a countdown from 3 minutes allowing the Phosphate reagent to mix and bubbles to settle.

 

[bulkrate]

On the flip side, if you're testing both the newly-mixed change water AND checking the level in your main tank to make sure you're not about to induce a swing - having two cuvettes is pretty darn handy for making the whole test session as short as possible.

 

[Adam]

Trizzino;1102436 wrote: If you hold the button down when you are on C2 test vial it starts a countdown from 3 minutes allowing the Phosphate reagent to mix and bubbles to settle.

To expand on this... what I've found helps with the Ultra Low Phos is before I start I put a clock on my phone that shows seconds. Then do it in this order with one cuvette.

1. I prepare the reagent packet.
2. Put 10ml in the vial.
3. Start the checker, at C1 I put the vial in and press the button.
4. Once the unit shows C2 I note the time and take the vial out.
5. Add as much of the reagent to the vial as I can get out of the packet then start shaking it as I watch the time.
6. At about 1:50 elapsed time (1 minute 50 seconds) I hold in the button to start the 3 min timer while still shaking the vial.
7. Once the reagent looks mixed well I let it settle for a few seconds then start inverting it slowly while rotating the vial. This clears the small bubbles.
8. Wipe the vial down good making sure the outside is clean. Then insert it into the unit to take the reading.

At the last step I usually have a little more than a minute left and the results are very repeatable, within 3-5ppb. This is the only Hanna test that you have to watch the time and doing it this way also helps me to be sure I don't miss the reading. I'm sure we've all put the vial in first then started the timer, set the thing down and walked away to do something else. Only to return to go :doh: as you look at a blank screen.

The key to Hanna, and all other tests for that matter, is starting with a clean vial. I keep a Tupperware container with RODI water in it that I use to rinse the vials as soon as the test is done then set them in a drying rack to use again. I can usually get 3 to 4 tests per vial before I need to give them a good cleaning.