Oscillating Alk Readings from Trident

[Formulator]

I added an apex trident to my system a few weeks ago and the Alk readings are constantly oscillating up and down by about 0.2 dKH. I have tried recalibrating and re-adjusting sample and reagent lines to ensure no kinks. It seems like it reads higher when testing all 3 parameters vs Alk only. You can see this demonstrated in the graph where I’ve triggered a manual test of Alk only and it deviates from the regular frequency of oscillation.

Please don’t mind the trends here. I have been messing with my dosing volumes and testing frequency trying to get them dialed in.

Anyone else had this issue with a trident and know how to fix it? I know its not a big deal in the grand scheme of things and I could probably just take the average and live with it, but for the amount of cash I forked out for the thing, I would expect better consistency.

 

[thedon986]

This is normal for the Trident. Don’t sweat it and just take the average. Here mine just after cleaning the sample vial and calibrating with my Hanna. Not sure what the latest jump is but the usually correct with the next test. I control with the DOS and it is very good about not overcorrecting from one test to the other dosage wise, it keeps it very consistent with minor changes just trying to nudge it one way or another.

 

[ariellemermaid]

This is normal for the Trident. Don’t sweat it and just take the average. Here mine just after cleaning the sample vial and calibrating with my Hanna. Not sure what the latest jump is but the usually correct with the next test. I control with the DOS and it is very good about not overcorrecting from one test to the other dosage wise, it keeps it very consistent with minor changes just trying to nudge it one way or another.

Like he said. However, your graph is too zoomed out to see: are you talking about 0.2 between tests, or throughout the day? Also, it looks like your manual tests are at a completely different time of day than the other ones. I’m curious what a manual test would show immediately after the automated test.

On the whole though, I only test twice a day. One combined and one Alk. My variance between the two tends to be more like 0.05, so I would say 0.2 is a lot. When I look at my second trident the AM-AM variance and PM-PM is more like 0.01-0.05. I can’t do that same analysis for the first one because I’ve been adjusting dosing a lot and adding kalwasser. It’s also hard to compare with the second one because I don’t know how the Trident controlled dosing is being adjusted during the day. Like if it increased the dosing after the morning test, then I would expect higher variance with the evening test, etc..

Also, you say you’ve been playing with dosing a lot. Are you taking that into account? I assume the unit is new, not used? Dosing to return chamber and testing in overflow chamber? Things like that?

 

[Formulator]

Like he said. However, your graph is too zoomed out to see: are you talking about 0.2 between tests, or throughout the day? Also, it looks like your manual tests are at a completely different time of day than the other ones. I’m curious what a manual test would show immediately after the automated test.

On the whole though, I only test twice a day. One combined and one Alk. My variance between the two tends to be more like 0.05, so I would say 0.2 is a lot. When I look at my second trident the AM-AM variance and PM-PM is more like 0.01-0.05. I can’t do that same analysis for the first one because I’ve been adjusting dosing a lot and adding kalwasser. It’s also hard to compare with the second one because I don’t know how the Trident controlled dosing is being adjusted during the day. Like if it increased the dosing after the morning test, then I would expect higher variance with the evening test, etc..

Also, you say you’ve been playing with dosing a lot. Are you taking that into account? I assume the unit is new, not used? Dosing to return chamber and testing in overflow chamber? Things like that?

I’m testing 6-8 times per day right now just trying to get a good handle on my daily consumption rate since I’ve never had the luxury of testing that frequently and was curious. What I’m trying to say is that the up and down correlates with testing Alk only vs all 3 since it alternates every test. In the screenshot below over 24 hours you can see the pattern. I marked up the photo so red is an Alk, Ca, Mg test, blue is Alk only test, and green is a manually triggered Alk only test. This can’t be real variation. Something is going on with the machine.

 

[Formulator]

This is normal for the Trident. Don’t sweat it and just take the average. Here mine just after cleaning the sample vial and calibrating with my Hanna. Not sure what the latest jump is but the usually correct with the next test. I control with the DOS and it is very good about not overcorrecting from one test to the other dosage wise, it keeps it very consistent with minor changes just trying to nudge it one way or another.

Thanks for the reply, but I’m not really seeing the same issue on your graph. Mine goes up and down predictably at every single test. And I’m not going to accept it as normal when Neptune states the precision is supposed to be +/- 0.05 dKH. It is good to know that the DOS won’t over correct with the variation though.

 

[ariellemermaid]

I’m testing 6-8 times per day right now just trying to get a good handle on my daily consumption rate since I’ve never had the luxury of testing that frequently and was curious. What I’m trying to say is that the up and down correlates with testing Alk only vs all 3 since it alternates every test. In the screenshot below over 24 hours you can see the pattern. I marked up the photo so red is an Alk, Ca, Mg test, blue is Alk only test, and green is a manually triggered Alk only test. This can’t be real variation. Something is going on with the machine.

Yeah now I understand. No, my units do not do that and I would consider that abnormal. It’s hard to compare our numbers because on one unit I do Trident controlled dosing and on the other I dose kalk at night plus an AM/PM 2 part bolus. On both I only do 1 combined AM test and 1 PM Alk test. With all of those caveats, in the past 3 tests the biggest variation was 0.05 between any consecutive test on either unit 12 hours apart.

I would reach out to Neptune with that picture and see what they say. You shouldn’t have 4h peaks and troughs of 0.21 unless your dosing is doing something wonky. Your manual test proves you can get 2 consecutive alike test precision.

Aside from that, every line in the Trident goes through an open 6 spoke “hub.” The different tests are done by clamping some lines and unclamping others (the clicks you hear). There’s just 1 central fluid pump. So maybe there’s some cross contamination from the last Mg to the next single Alk? Or something going on between the two consecutive Alk’s. Can’t think of any other mechanical explanations. One thing you could check: on the front above the tray there’s a black arch with a Neptune symbol. It’s just a plate that slides up and into place. I’ve had mine apart so many times I can barely get it to stay. If you can pop that off easily you can view the test vial. I would make sure it’s fully empty after the combined set and the single are done.

You might also try going down to the minimum (3 tests?) one day and see if that makes a difference.

For more data, I would do a test kit immediately after (or heck during) the combined and the single. I’m just curious which has closer correlation.

 

[Formulator]

Thanks. I will do some further inspection as you suggested. I have done a manual test and the high readings are most accurate. Also, an important edit - I misstated which was which earlier. The peaks are Alk only and the valleys are all 3. so it is more accurate when testing Alk only, which adds credence to your idea that there could be some kind of interference when testing all 3.