Is it safe to trust our test kits?

[X-37B]

Here is the alk making standard.

DIY alkalinity standard

For folks who may want to evaluate the accuracy of their alkalinity test kits, here are two suggested ways to do it. One is DIY and one is a mostly commercial standard with one DIY step. Method 1 Standard solutions could be made with sodium bicarbonate, but it can be hard to be sure it hasn't...

www.reef2reef.com

 

[muzikalmatt]

As others have indicated, I don't think it's necessarily the unit itself that's causing the discrepancy between readings, it's the reagent. I've had similar issues with the Hannah alkalinity reagent getting old and providing incorrect readings. I typically keep multiple bottles of reagent on hand, as well as a second alk test kit (Salifert) to double-check things if I'm questioning the results from the Hannah checker. As others have said: "Trust, but verify."

 

[trmiv]

I stopped using the Hanna alk checker because of this reason. Every time I opened a new bottle of reagent my readings would be significantly different from the previous bottle. The old bottle would drift significantly over time as it was opened. What I like about the single use powdered reagents from their Nitrate and phosphate checkers is there isn’t a way for the reagent to get contaminated as I gets older like the alk reagents.

I get much more consistent, repeatable results from my Trident backed up with my Salifert alk kit so that’s what I’m sticking with.

 

[vahegan]

As for Hanna's alkalinity egg, I have noticed that sometimes the seal between the rubber nozzle and the 1ml syringe leaks air and when you fill it with reagent it starts to drip once you lift the tip from the bottle. This may result in inconsistent readings as different amount of reagent will go in the water sample each time. Now I wet the syringe tip before attaching the nozzle and this seems to provide a tight seal.

As for the quality of tests in general, I was completely pi$$ed off at Red Sea Nitrate Pro. I liked the nice setup with color disk and a reference cuvette they are providing and ordered the kit when my Salifert ran out. Due to some circumstances my tank has cycled and then my nitrate checks were consistently giving extremely high readings while the phosphate was at zero. The nitrate test was red (beyond the maximum color mark of the test) even when I diluted the water sample with RO water, 1:15 (as the instructions for high-range suggested). So I was assuming that for some reason my nitrate reading was over 100ppm and started taking drastic measures. Daily 10% water changes, plus gradually increasing doses of phosphate and organic carbon for 2 weeks were still showing the same dark red color even for the diluted test. I was growing mad and then I decided to check with the remains of my Salifert (which was a few months out of date already) - and it tested zero! I then tested RO water sample with Red Sea, and it was showing the same super-high red color. I am mad with Red Sea now, would not trust anything from this company anymore - I nearly dumped my reef because of their bad test. I am now planning to buy the Hanna Nitrate checker (high range), I especially like the sealed reagent packs which are accurately measured in each packet and are unlikely to go bad due to contact with air or moisture over time...

 

[jgirardnrg]

As for Hanna's alkalinity egg, I have noticed that sometimes the seal between the rubber nozzle and the 1ml syringe leaks air and when you fill it with reagent it starts to drip once you lift the tip from the bottle. This may result in inconsistent readings as different amount of reagent will go in the water sample each time. Now I wet the syringe tip before attaching the nozzle and this seems to provide a tight seal.

As for the quality of tests in general, I was completely pi$$ed off at Red Sea Nitrate Pro. I liked the nice setup with color disk and a reference cuvette they are providing and ordered the kit when my Salifert ran out. Due to some circumstances my tank has cycled and then my nitrate checks were consistently giving extremely high readings while the phosphate was at zero. The nitrate test was red (beyond the maximum color mark of the test) even when I diluted the water sample with RO water, 1:15 (as the instructions for high-range suggested). So I was assuming that for some reason my nitrate reading was over 100ppm and started taking drastic measures. Daily 10% water changes, plus gradually increasing doses of phosphate and organic carbon for 2 weeks were still showing the same dark red color even for the diluted test. I was growing mad and then I decided to check with the remains of my Salifert (which was a few months out of date already) - and it tested zero! I then tested RO water sample with Red Sea, and it was showing the same super-high red color. I am mad with Red Sea now, would not trust anything from this company anymore - I nearly dumped my reef because of their bad test. I am now planning to buy the Hanna Nitrate checker (high range), I especially like the sealed reagent packs which are accurately measured in each packet and are unlikely to go bad due to contact with air or moisture over time...

If your syringe tip leaks air it's time for a new one.

 

[vahegan]

If your syringe tip leaks air it's time for a new one.

It was brand new out of the box. Hardly used it 2 or 3 rimes.

 

[jgirardnrg]

It was brand new out of the box. Hardly used it 2 or 3 rimes.

I had one like that as well. Luckily, I keep a stockpile of the things. The ones that leaked air didn't even pull up the correct amount of reagent.

 

[vetteguy53081]

Often, readings are either regarded as false or offering crazy numbers.
If a person changes water or adds chemicals abd decides its time to do some water testing. . . Wait 8-12 hours to test for accuracy.
It is true that API are notorious for false readings. They are IMO good for reference - getting an idea if levels may be climbing.

 

[Salted]

I am now planning to buy the Hanna Nitrate checker (high range), I especially like the sealed reagent packs which are accurately measured in each packet and are unlikely to go bad due to contact with air or moisture over time...

Dispensing the powdered reagent from the packet has its own little set of challenges. It is a very fine powder. I find that the po4 reagent pours pretty reliably out of the packet. The no3 reagent I find sticks to the packet. I pour what I can then rub a toothpick around inside the packet to get the last little bit. And there is user error. When pouring and I see a few grains spill off and out I wonder if I’m skewing my test. Also there very little reagent, so like anything else we’re relying on the manufacturer to have the amount correct. In the end I still prefer Hanna over trusting my eyes to match color.

 

[vahegan]

Dispensing the powdered reagent from the packet has its own little set of challenges. It is a very fine powder. I find that the po4 reagent pours pretty reliably out of the packet. The no3 reagent I find sticks to the packet. I pour what I can then rub a toothpick around inside the packet to get the last little bit. And there is user error. When pouring and I see a few grains spill off and out I wonder if I’m skewing my test. Also there very little reagent, so like anything else we’re relying on the manufacturer to have the amount correct. In the end I still prefer Hanna over trusting my eyes to match color.

Well, when you want to make that spoon level, there is always a chance to have quite a few grains extra or less than needed. This is all a calculated part of measurement accuracy. But still I believe that factory-measured and sealed packets of reagents are a amore accurate measure than when the user has to do the measuring. And, most importantly, single-use reagents are not contaminated by air and moisture as opposed to opening and closing the jar each time. And yes, of course the electronic determination of the color is much more accurate than color matching we do with the eye... Especially when the colors do not seem to match

All of this said, I believe that test chemistry is chosen such that it is not too sensitive to the exact amount of reagents added. Unless of course, when it is a titration test.

 

[Malcontent]

A few years ago I weighed the contents of some Hach ammonia packets.

salicylate:

473.41 mg
467.07
478.73

cyanurate:

580.40 mg
607.63
611.17

So they're not that precisely measured and probably don't have to be.

 

[StewL6]

I highly recommend a Single-channel Pipettor adjustable 1 to 10 ML and one 100 to 1000 micro liters I have both with extra tips makes everything so easy and a lot more accurate and they are cheap. Makes the Hanna Calcium checker very repeatable. I spend more time cleaning the checker and culvettes then I do testing

 

[vahegan]

I highly recommend a Single-channel Pipettor adjustable 1 to 10 ML and one 100 to 1000 micro liters I have both with extra tips makes everything so easy and a lot more accurate and they are cheap. Makes the Hanna Calcium checker very repeatable. I spend more time cleaning the checker and culvettes then I do testing

I actually have an adjustable 1-10ml pipettor. Bought it for taking water samples for tests, but hardly ever use it. It's sort of large and I am lazy to take it out of its own box. Those 10ml syringes are much smaller and I store them in Hanna's boxes and I tend to use these instead. But I never got the Calcium test, I was reading rather negative reviews on it and wasn't even considering buying it. I was thinking of choosing one larger box for all Hanna photometers and their stuff, and when I get at that I will probably make room for the pipettor to fit in there as wellas well. I have the Phosphate and Alkalinity so far, was planning on get the Nitrate HR and probably a salinity (conductivity) meter.

It is tempting to buy the Calcium meter too, although the reagents for it are the most expensive for some reason. Do you say that negative reports on this checker are mostly because of inaccurate doses of reagents added during the test?

I actually believe that the tests that normally are carried out by titration should be carried out just that way rather than by color change when a known amount of reagent is added. I would rather use an automatic titrator but that falls in a different price range, unless I DIY one... And, I was surprised that Hanna's alkalinity tester actually works quite well. Anyone knows what's in that reagent they are using? I wish I could make a DIY replacement for it.

 

[mdb_talon]

In the end I still prefer Hanna over trusting my eyes to match color.

I think that is pretty much all that hanna has going for it. Differentiating colors can be a big guessing game. I still mostly use hanna for nitrate and phosphate just for this reason. However I use titration based tests for alk/calc because in my experience they are more consistent and accurate (even if reading is not as precise) and as long as you can tell the difference between two colors that are significantly different they are easy to "read".

 

[Malcontent]

I think that is pretty much all that hanna has going for it. Differentiating colors can be a big guessing game. I still mostly use hanna for nitrate and phosphate just for this reason. However I use titration based tests for alk/calc because in my experience they are more consistent and accurate (even if reading is not as precise) and as long as you can tell the difference between two colors that are significantly different they are easy to "read".

Some (most? all?) titrations can be done with a pH meter instead of a color change indicator but it would make the tests a bit more involved. OTOH, if you want ultimate accuracy...

 

[mdb_talon]

Some (most? all?) titrations can be done with a pH meter instead of a color change indicator but it would make the tests a bit more involved. OTOH, if you want ultimate accuracy...

What would be the benefit in our case? Titration tests are reasonably accurate(not perfect), easy, and consistent.

 

[Malcontent]

What would be the benefit in our case? Titration tests are reasonably accurate(not perfect), easy, and consistent.

Not having to tell the difference between two colors.

 

[mdb_talon]

Not having to tell the difference between two colors.

Unless someone is severely color blind i cant imagine that is an issue in titration tests. Even most colorblind people i imaging would have no issue.

 

[Rick's Reviews]

As with all test kits, they all have individual uses, I believe Hanna test kits are accurate when new, however if not properly maintained and if you do not clean salt of any electronic equipment it can change the readings drastically upon your next test, even simple battery change can change readings, you will always fall back on to normal simple water test... Whichever brand you use

 

[vahegan]

Some (most? all?) titrations can be done with a pH meter instead of a color change indicator but it would make the tests a bit more involved. OTOH, if you want ultimate accuracy...

For alkalinity that is true, but I don't think that pH meter would do you any good for tests that titrate with Trilon B or other similar complexant, i.e. calcium, magnesium tests.

As for determining the titration endpoint, it is not also very easy as the color change is not exactly sharp. When you need to determine between pure blue or blue which has some red in it, you do not need to be colorblind to feel confused. Electronic tests are much more accurate and consistent in finding the exact edge of this color change.