How Accurate Should Test Equipment Be?

[Reefer Matt]

Hey Reefers!
A lot of buzz is about with new testing equipment that just came to market. But just how accurate do you expect them to be for the price? Should they be dead on accurate, or is in the ballpark acceptable? I generally expect expensive tests to be the most accurate, but that isn’t always the case with hobby grade equipment. What’s your expectations?

 

[14 foot reef]

I treat most hobby test kits as a baseline trend measurement, I never expect 100% accuracy from hobby grade kits.

 

[drolmaeye]

I don't have a good answer as far as acceptable accuracy, but I can say that I generally care more about precision and repeatability. If I can measure an Alk of 8.8 dKH ten times in a row (but the true Alk is 8.3 dKH because of poor accuracy) then I am happy. I will be able to monitor the Alk trends (momentary and long-term) in my tank and make changes as needed. True there will be a small offset from the true value, but in most instances I don't think that's a significant concern.

 

[Biokabe]

I don't have a good answer as far as acceptable accuracy, but I can say that I generally care more about precision and repeatability. If I can measure an Alk of 8.8 dKH ten times in a row (but the true Alk is 8.3 dKH because of poor accuracy) then I am happy. I will be able to monitor the Alk trends (momentary and long-term) in my tank and make changes as needed. True there will be a small offset from the true value, but in most instances I don't think that's a significant concern.

I echo this sentiment. With a few exceptions, it doesn't really matter what the exact value is. The reason for testing is to monitor and control changes, not to pin your water parameters at a specific value.

An exception to that would be any parameter that can be deleterious outside of a narrow window. For example, copper. Whether you're monitoring copper concentration as part of a QT procedure or trying to rule out a problem in your display tank, you need an accurate picture of what is actually in your water. Regardless of why you're testing for copper, if the actual value is too far from the tested value you can be in trouble very quickly.

So the answer is basically, "It depends." If a broad range of values can be acceptable (Alk, Calc, Mg, Nitrate) then it's okay if the test isn't terribly accurate, so long as it's always wrong in the same way. If the band of acceptable parameters is narrow or nonexistent, then it's important for the test to be both accurate and precise.

 

[ryanjohn1]

Only really need a decent ball park between icp testing. Hanna is good for some stuff and salfert for some.

 

[VintageReefer]

Call me crazy but this is 2024 and I should be able to get an accurate exact temperature of my water quickly and easily. The market is ridiculous. My heater controller says one thing. The heater itself says another. My digital thermometer probe says another thing. An IR thermometer gun says another thing. And if I take the lowest measurement and highest I have a variance of almost 3 degrees. So something is reading on the low of their “accepted range” another is on the high side; and the others are somewhere in between. Which one is right?

Why can I not buy a device to actually and simply tell me the exact temperature of my tank. This isn’t chemistry. What’s the friggin temp?

 

[KrisReef]

Precision vs Accuracy, the terms matter.

For our test kits, I think of precision as the repeatability of test results given the same amount of unknown parameter that we are testing in a water sample.

Accuracy is getting the correct result and telling us what the true value of the unknown parameter really is.

Sloppy testing habits can render the most accurate testing kit imprecise, while no amount of proper protocols can help an imprecise test kit provide an accurate result (that can be trusted).

 

[CKW]

Hey Reefers!
A lot of buzz is about with new testing equipment that just came to market. But just how accurate do you expect them to be for the price? Should they be dead on accurate, or is in the ballpark acceptable? I generally expect expensive tests to be the most accurate, but that isn’t always the case with hobby grade equipment. What’s your expectations?

In my opinion consistency is slightly more important than accuracy. One can compensate for accuracy but not for inconsistency.

 

[Malcontent]

Call me crazy but this is 2024 and I should be able to get an accurate exact temperature of my water quickly and easily. The market is ridiculous. My heater controller says one thing. The heater itself says another. My digital thermometer probe says another thing. An IR thermometer gun says another thing. And if I take the lowest measurement and highest I have a variance of almost 3 degrees. So something is reading on the low of their “accepted range” another is on the high side; and the others are somewhere in between. Which one is right?

Why can I not buy a device to actually and simply tell me the exact temperature of my tank. This isn’t chemistry. What’s the friggin temp?

Buy a calibrated platinum RTD thermometer. Adjust everything else to match.

 

[X-37B]

Call me crazy but this is 2024 and I should be able to get an accurate exact temperature of my water quickly and easily. The market is ridiculous. My heater controller says one thing. The heater itself says another. My digital thermometer probe says another thing. An IR thermometer gun says another thing. And if I take the lowest measurement and highest I have a variance of almost 3 degrees. So something is reading on the low of their “accepted range” another is on the high side; and the others are somewhere in between. Which one is right?

Why can I not buy a device to actually and simply tell me the exact temperature of my tank. This isn’t chemistry. What’s the friggin temp?

Its 2024 get a stick on temp strip.
It hangs right there with my Aqualogic controller and my mercury themometer.
Mercury by far the go to but all are within 1 degree.
I have several but my favorite mercury only reads between 70-80°F.