Testing calcium.. first used the Hanna said 465 a bit high but not crazy been steady 440-450 used a Red Sea it said 360 ??? Redid Hanna now it went to 530 did ted sea again 380.. it’s been very steady for a long time but I’m like what the?? Any ideas?
Calcium reading crazy
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flampton
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Do you have the calibration fluid for the Hanna? I know from others that with Hanna if you don't have exactly 100ul you will have results that are off. I'd check with the calibration fluid, and if you don't have that I would trust the Red Sea test over the Hanna checker
flampton
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I do if you have no way to calibrate the Hanna, and even then if you look at other peoples experience they really dislike the Hanna, that's why I never purchased it. I'm currently using the Red Sea Pro version and am very happy with it. I'm not sure if they have a non-pro version but that may be a bit less accurate? I'll let some others chime in who have used the Hanna.
Randy Holmes-Farley
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The Hanna is a poor design that is freakishly sensitive to calcium in the blank. I’m not sure if that is an issue here.
IMO the Hanna “standard” Is not that useful. It doesn’t check anything except the electronics. Not the reagents or user methodology. I’ve not heard of anyone who used it and found a problem, but there certainly could be folks who have.
IMO the Hanna “standard” Is not that useful. It doesn’t check anything except the electronics. Not the reagents or user methodology. I’ve not heard of anyone who used it and found a problem, but there certainly could be folks who have.
flampton
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Interesting did not know that. Thanks for letting me know the calibration fluid isn't that useful either. I'm glad I stayed away.
I have the Hanna and the Red Sea Pro. The hanna was a pain to use so I have not used it in years. I measured CA at 450 with Red Sea and Triton test came back at 471. My Trident is showing 410-420 (but I only monitor this for changes, I generally don't trust it to be 100% accurate
). I am ok w/ the differences in the tests, I just try to keep it pretty stable and targeting mid 400s. Also I use a CA reactor and I hardly ever adjust CA. I dial the CA reactor into keep alkalinity where I want it and CA stays pretty stable.
). I am ok w/ the differences in the tests, I just try to keep it pretty stable and targeting mid 400s. Also I use a CA reactor and I hardly ever adjust CA. I dial the CA reactor into keep alkalinity where I want it and CA stays pretty stable.
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Its just a sealed cuvette with a fixed absorbance to check.
flampton
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Oh wow I just looked and they don't sell 'true' calibration fluid for any meter except for the pH meter. Everything is just colorimetry checkers. I wonder if anyone has made their own stock solutions to check whether 1. it's easy to use the kit well, and 2. whether the units are truly within the margin of error given. I've not jumped into Hanna because I don't mind the Red Sea kit and my eyesight is still okay for this. But maybe someday unless I fall into a cheap spec.
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Following essentially the same method as described in the video by @takitaj (Well done!!) with the exception of the pipette...I use a 10-100ul pipette that I found to be even more accurate than the Hanna provided one (link here )
I ran a series of standards 300, 350, 400, 450, 500 ppm in 35 ppt Salt Water made from RODI and Reagent Grade Sodium Chloride. I ran 10 tests at each level and calculated the Relative Accuracy and Precision at each level. I was going to do a video much like @takitaj but have been traveling down a lot of Rabbit Holes...but he saved me the time...So now I will just post my results.
As you can see the Checker can yield some very good results...But in this particular test the details matter and good lab practices pay off..IMO
I ran a series of standards 300, 350, 400, 450, 500 ppm in 35 ppt Salt Water made from RODI and Reagent Grade Sodium Chloride. I ran 10 tests at each level and calculated the Relative Accuracy and Precision at each level. I was going to do a video much like @takitaj but have been traveling down a lot of Rabbit Holes...but he saved me the time
...So now I will just post my results.As you can see the Checker can yield some very good results...But in this particular test the details matter and good lab practices pay off..IMO
Thanks Rick Mathew but I didn't make the video. It was one I watched and followed it closely. I got similar results and I checked against the Red Sea Pro several times before I felt comfortable trusting the results. The Hanna was consistently within 20 or so points of the Red Sea tests. I also found it was a little more accurate using the distilled water vs 0 TDS rodi water.
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