Proof: Never trust test strips.

Hey guys,
Here's another proof of why you should never trust test strips to measure your water chemistry.

Here's a set of test strips from SERA and these are the test results:

Nitrite: 0.25 ppm
Nitrate: 5 ppm






Just 1 min later these are the results with API Freshwater test kit:





Conclusion: Never ever test your water parameters with test strips.

 

Thanks Saqib!

Ken

 

Lol. I hate how Petco always uses test strips to test your water. It just shows how bad the info the give you can be.

 

I feel like this should be stickied or something. Photographic evidence for non-believers of why liquid kits are worth the extra initial cost! Thanks for the pictures

 

Now the truth has been brought into the light...

 

Go to the light! Go to the light!

I have always advocated against test strips. I'm not sure what they cost, but knowing that you can get the API master kit for less than $18 on-line, and that kit lasts for hundreds of tests, I presume that the master kit is more cost-effective as well as results-effective.

 

Some people just don't have the math skills and common sense to figure that out LyndaB. Not to mention dedication to their fish

 

Go to the light! Go to the light!

I have always advocated against test strips. I'm not sure what they cost, but knowing that you can get the API master kit for less than $18 on-line, and that kit lasts for hundreds of tests, I presume that the master kit is more cost-effective as well as results-effective.

Even if you pay twice that -- which I did, I think -- in the LFS, it's still cheaper than buying test strips.

The idea of spending $30 (give or take) to test the water quality just gives new aquarists a little sticker shock, I think. Live and learn.

 

Thankfully before I went out and purchased all the equipment I needed for my tank, I did my research and picked up the API master kit...

But why is there such a discrepancy between test strips and liquid kits? Does anyone actually know the answer (or for that matter, the chemistry involved with the test strips)? I can't understand how it could be anything beyond a simple calibration issue... i.e.:

Company A gathers samples of water with different known concentrations of NH4, NO2, NO3, and known pH's. They then soak their test strips in the samples, observe the results, and from there, create a color grade of the known values.

Otherwise, if it isn't that simple that means either:

1) The product somehow changes between the date of manufacturing and use, or

2) Interactions with different combinations of chemicals in the water skew results, which in the end results in the test strips not highlighting values of discrete chemicals, but rather producing a unique 'barcode' of the chemistry present in the water, which isn't helpful at all.

Thanks for highlighting this. Could be useful for others!

 

Ken

 

I would like to add that not ALL test strips are bad. I actually use them from time to time because I want some of the results that are on them and they are so much faster to attain than dealing with their liquid counterparts (and cheaper due to frequency).

Things are only as accurate as you make them. If you are not perfectly precise with the liquid kits they will be inaccurate as well, I did a test at work with liquid kits and how being off only a small amount on the quantity of water can change the results. Yes, I do use the liquid kits but it also made me take a look at how I was performing the tests, if you are being very ho hum about doing the test and just more of going thru the motions your results will vary. Now all that being said, if you continue for quite a while doing the test the same way, your results we become meaningful once again as you have a larger baseline to work with for an understanding.

As an example of that if you constantly run your 5ml nitrate test with 6ml of water, your result will be different (usually lower) than what it should be. If you only did this once this is a very inaccurate test. However if you do this same test for months this way, yes your tests will still be inaccurate but you will be able to see patterns of rising and falling levels and be able to take actions appropriate.

To me the conclusion of this is not that one is so much worse than the other, it is merely that getting a usable result is the most important.

 

Don't forget to shake those nitrIte test solutions thoroughly or you could get a low reading. At least 30 seconds...I shake them for 2 minutes because I rarely use them and they sit for a long time. Tapping them on the table as you shake them helps to be sure.

Also a cheap syringe is the easiest way to precisely fill testing tubes.

:

 

I know this is a tad delayed but I have to agree with your post. An anxious person by nature, I use both test strips and liquid test (API)

With API 5-1 strips, the nitrate level was between the colours for 0 and 20ppm
With the API liquid test it was reading again between 10 & 20 ppm
With Sentry brand 5-1 strips, the nitrate pad turned a dark grey with black specks on it 0.o
I did the Sentry test first, and after seeing that you can imagine I had a minor panic attack, but after doing 2 follow up tests I was relieved.

Anyway the point of this reply is to provide another example of the variation of reliability of test strips (from brand to brand, and batch to batch, etc.)

So yeah - API Master Test Kit = One of the most reliable avenues for testing water at home.

 

I pound my nitrite bottle on the counter a couple times then shake it! Overkill maybe?

 

Pound the Kraken!!!