Test Error Poll

[Randy Holmes-Farley Verified Community Expert]

Have a weird test result?

It is very likely test error rather than some new and wonderful chemistry.

pH 7.4? 8.8?
Magnesium jumped 50 ppm in a week?
Calcium declined 50 ppm in a day?
ORP is 13 mV?

Test error. it is way more common than you probably think.

 

[cracker]

I'm figuring that out pretty quick ! Usually it's the tester's (Me) fault not the kit .

 

[PiscesPower]

If I get what I think is a very unexpected results, I always test another 2 times.

 

[Chris Villalobos]

My Phosphate Hanna Checker will show. 0.03 PPM, 0.00 PPM, and 0.08 PPM with the same test vials. It seems worse if I use two vials instead of one but who knows!

 

[jsker]

I will go with over half, I am guilty of not testing correctly.

 

[lillypads reef]

Randy, how can we beat this problem?

Should i just be more careful measuring when i use hobby grade kits? I use hannah or Salifert. Or do you recommend ICP test done more frequent?

 

[Randy Holmes-Farley Verified Community Expert]

Randy, how can we beat this problem?

Should i just be more careful measuring when i use hobby grade kits? I use hannah or Salifert. Or do you recommend ICP test done more frequent?

One thing that most of us are guilty of (myself included) is to rush to correct a problem. If we are not sure there is a problem, or are not sure why, then the correction could actually cause a problem when none actually exists, or make it worse when the issue self corrects.

So when you get a sudden change in a value (say, calcium or salinity) that typically cannot change suddenly, take a deep breath and think about whether it makes sense. Could it even be real? Obviously if you knew you overdosed something yesterday by mistake, it is likely real. If you did not, it very likely is not.

If it is not an emergency (e.g., not high ammonia or some such critical issue), maybe don't do anything except look over the system for problems. Test again the next day to see if the "problem" changes.

Double check weird results with your own kit, then maybe a borrowed kit. I've occasionally left out steps in some multistep kits that I used a lot. Instantly gives a weird answer. Time to take a step back and think everything through. Could nitrate have dropped from 10 ppm to 0 ppm overnight? Etc.

 

[brandon429]

The API .25 ammonia misread must be offered as the single most enduring and impactful test kit error in the history of our hobby. No, a cycle doesn't last seven months.

Please for an updated article someone take time to compile known lab samples of common params mixed in different ratios from miniscule to obviously high and mail them out to participants who test only numbered vials and report back

calcium
nitrate trite ammonia
Po4
Mg
All the params

Writer assembles all those against the known levels and we get an '18 update on test compliance in the hobby using the range of today's options. Include ammonia both set at real .25 and at zero and at .5 ideally.