Alkatronic and Baseline Dosing

[David S]

Hi

I've been using an Alkatronic to monitor my tank's alkalinity for 2 months now.
Generally, it worked really well.
For example, it showed significant changes in alkalinity over a 24 hour period, which I was able to correct by dosing at specific times.
And while it's readings did not match my Salifert tests, which is very reliable, they were within 0.3 DKH of each other, which I considered acceptable.
However, I had not done a Salifert test for over a week and when I did i discovered the DKH readings from the Alkatronic was reading over 2 DKH higher than the Salifert.
I have no explanation for the sudden divergence. Any ideas?
I tried using the "baseline calibration" feature in the Alkatronic, which I assumed, perhaps incorrectly, was a way of adjusting the Alkatronic reading to a third part result.
So I divided my Salifert result by the Alkatronic result and a decimal figure shows up in the app, which presumably is the correction factor that the Alkatronic uses to modify its result to correspond to my Salifert result.
The first time I tried it, it seemed to work but shortly thereafter the Alkatronic reverted to the high readings.
I also noticed that when I tried to redo the calibration it doesn't work.
The decimal adjustment number shows up (I save it in the app) but when I exit the screen and then go back, I no longer see the decimal. Furthermore, the baseline calibration field is grayed out and says NA- presumably not available. I've tried redoing the calculation numerous times but it fails every time.
I have sent a similar message to Focustronic and am awaiting their reply, but I was wondering if anyone else can shed some light on this.
Thanks

 

[David_CO]

in general I've found that salifert reads ~.3 dkh lower than ph reagent based testers (alkatronic and KH keeper). overtime the alkatronic will drift out a bit (as will all ph reagent testers) and will need to be re-calibrated. I do it once every few months, not as much as they want.

The absolute value of the results isn't that important. you want to know trends and make sure over a time interval the values are within a range that's acceptable to you.

here is a doc on the "baseline calibration", i've never used it and I dont think many would recommend utilizing it.

https://focustronic.com/wp-content/uploads/2022/03/Tip_how_to_use_the_baseline_cal.pdf
Make sure your reagent is mixed accurately and that their are no kinks in the hoses and they are within the height limits dictated in the user guide.

 

[dwest]

Hi

I've been using an Alkatronic to monitor my tank's alkalinity for 2 months now.
Generally, it worked really well.
For example, it showed significant changes in alkalinity over a 24 hour period, which I was able to correct by dosing at specific times.
And while it's readings did not match my Salifert tests, which is very reliable, they were within 0.3 DKH of each other, which I considered acceptable.
However, I had not done a Salifert test for over a week and when I did i discovered the DKH readings from the Alkatronic was reading over 2 DKH higher than the Salifert.
I have no explanation for the sudden divergence. Any ideas?
I tried using the "baseline calibration" feature in the Alkatronic, which I assumed, perhaps incorrectly, was a way of adjusting the Alkatronic reading to a third part result.
So I divided my Salifert result by the Alkatronic result and a decimal figure shows up in the app, which presumably is the correction factor that the Alkatronic uses to modify its result to correspond to my Salifert result.
The first time I tried it, it seemed to work but shortly thereafter the Alkatronic reverted to the high readings.
I also noticed that when I tried to redo the calibration it doesn't work.
The decimal adjustment number shows up (I save it in the app) but when I exit the screen and then go back, I no longer see the decimal. Furthermore, the baseline calibration field is grayed out and says NA- presumably not available. I've tried redoing the calculation numerous times but it fails every time.
I have sent a similar message to Focustronic and am awaiting their reply, but I was wondering if anyone else can shed some light on this.
Thanks

I would test with a different test kit (or take to LFS) to see which of alkatronic or Salifert is wrong. I agree a few tenths dKH difference is no biggie, but there should not be anywhere near a 2 dKH discrepancy.

Or test them both with a standard.

I agree that recalibrating the alkatronic might help, if it’s found to be wrong, although it’s tough to get that far off. Check that the alkatronic hoses are held in their places properly and not a lot of air is present in the lines.

I have toyed with baseline calibration with alkatronic but don’t think it’s something I’d mess with again.

The only time I’ve had a discrepancy over 0.4 dKH (I use Hanna checker for comparison) is when yours truly diluted the alkatronic reagent incorrectly.

 

[David S]

in general I've found that salifert reads ~.3 dkh lower than ph reagent based testers (alkatronic and KH keeper). overtime the alkatronic will drift out a bit (as will all ph reagent testers) and will need to be re-calibrated. I do it once every few months, not as much as they want.

The absolute value of the results isn't that important. you want to know trends and make sure over a time interval the values are within a range that's acceptable to you.

here is a doc on the "baseline calibration", i've never used it and I dont think many would recommend utilizing it.

https://focustronic.com/wp-content/uploads/2022/03/Tip_how_to_use_the_baseline_cal.pdf
Make sure your reagent is mixed accurately and that their are no kinks in the hoses and they are within the height limits dictated in the user guide.

Thanks so much for your replies.
I have been contacted by a rep from Focustronic and here is what we have determined so far:
There doesn't seem to be a problem with the Alkatronic reagent.
I ran the test that is recommended to compare the Salifert result with the Alkatronic reagent and they were within 0.1 DKH for the test I did.
I think I need to recalibrate the Alkatronic's PH probe as it is showing a much lower reading than my Apex probe.
Problem is I don't have a PH 4 calibration packet - which is what the Alkatronic probe uses.
Hopefully my LFS has one.

 

[David_CO]

Thanks so much for your replies.
I have been contacted by a rep from Focustronic and here is what we have determined so far:
There doesn't seem to be a problem with the Alkatronic reagent.
I ran the test that is recommended to compare the Salifert result with the Alkatronic reagent and they were within 0.1 DKH for the test I did.
I think I need to recalibrate the Alkatronic's PH probe as it is showing a much lower reading than my Apex probe.
Problem is I don't have a PH 4 calibration packet - which is what the Alkatronic probe uses.
Hopefully my LFS has one.

FWIW my alkatronic PH always reads way lower than my apex. like .4-.5 PH, not convinced thats it but worth a try. You absolutely need to use the 4 and 7 calibration solutions.

 

[David S]

That's good to know.
Thanks

 

[DiscoStuart]

I ran the test that is recommended to compare the Salifert result with the Alkatronic reagent and they were within 0.1 DKH for the test I did.

What was this test / how do you do it?

Edit: Is this the one for the baseline calibration that requires you to have the pre-mixed Alkatronic solution? Or is there another way?

 

[David S]

What was this test / how do you do it?

Edit: Is this the one for the baseline calibration that requires you to have the pre-mixed Alkatronic solution? Or is there another way?

It's been awhile since I did it and as I recall there is somewhat confusing documentation. I'll try to check exactly what I did.

 

[David S]

It's been awhile since I did it and as I recall there is somewhat confusing documentation. I'll try to check exactly what I did.

Ok.
If you look at pages 30 and 31 of the Alkatronic manual, which can be found on the Focustronic website, it describes how to compare the Alkatronic reagent result with the Salifert. I will summarize.
First, you will start out running the Salifert test, but instead of using, the 4 drops of Salifert dye you use 4 drops of Alkatronic reagent (already mixed with RODI)
Then add Salifert reagent and when it changes color look to see the ml level in the chart provided by Salifert.
Then multiply that amount by 250 and then by 0.056.
( Ml X 250 X .056)
This gives you the adjusted DKH using the Alkatronic reagent.
Then take a normal Salifert test
Then compare the final results.
For me, they were very close.
That suggested, to me, that the Alkatronic reagent was fine (as I KNEW the Salifert was accurate).
So the problem was the Alkatronic unit itself.
No problem though. As the inaccuracy was consistent, I've been using the "baseline calibration/compensation", in the Alkatronic
I use a ratio of 0.8 and ever since (knock on wood) my Alkatronic readings have matched up with my occasional Salifert spot checks.
Hope this helps

 

[DiscoStuart]

Ok.
If you look at pages 30 and 31 of the Alkatronic manual, which can be found on the Focustronic website, it describes how to compare the Alkatronic reagent result with the Salifert. I will summarize.
First, you will start out running the Salifert test, but instead of using, the 4 drops of Salifert dye you use 4 drops of Alkatronic reagent (already mixed with RODI)
Then add Salifert reagent and when it changes color look to see the ml level in the chart provided by Salifert.
Then multiply that amount by 250 and then by 0.056.
( Ml X 250 X .056)
This gives you the adjusted DKH using the Alkatronic reagent.
Then take a normal Salifert test
Then compare the final results.
For me, they were very close.
That suggested, to me, that the Alkatronic reagent was fine (as I KNEW the Salifert was accurate).
So the problem was the Alkatronic unit itself.
No problem though. As the inaccuracy was consistent, I've been using the "baseline calibration/compensation", in the Alkatronic
I use a ratio of 0.8 and ever since (knock on wood) my Alkatronic readings have matched up with my occasional Salifert spot checks.
Hope this helps

Super helpful - I’ll try it out. Thank you!

I probably need to recalibrate after hose break in. That being said, even if it is off slightly, it is super consistent. And I struggle to get the exact same color change point on salifert each time.