The most common answer is…

[Pankney72]

Ever wonder what the most common answer is at REEF2REEF?

I’m certainly biased based on what threads I actually read, but I think it is this:

Test error!

Seriously, if you get an unexpected test result of any kind and need to ask about it, the best answer is very often test error.

Always doubt any unusual result!

Don’t try to fix it until you are sure it is real.

If you are a new hobbyist and get any result that you are considering asking about, start off by not believing it! Then ask folks.

Not every result is possible, even when you repeat it.

Do tests kits publish standard error? I could check my own kits for the info but that’s like 30ft away.

 

[BanjoBandito]

“Test until you get the results you want”

 

[BanjoBandito]

The most posted response is a a request for parameters - “what are your parameters?”!

 

[ZombieEngineer]

Do tests kits publish standard error? I could check my own kits for the info but that’s like 30ft away.

The good ones do, but they never include typical user mistakes.

For example, my red sea calcium test is stated as an accuracy of 5ppm. What this does not factor in is I could have

1. Dropped 1 less drop than actual titration equilibrium.
2. Had trouble reading the vial and read 1 ml less than actually used.
3. Left the lid open long enough that over time the titrant evaporated some.

Add those three errors together and now we are off by 30-40ppm. And this is only a couple minor issues that are really common.

 

[Freddy0144]

I am currently bothered by this entire testing thing as of when I started this tank. I have taken my water samples to the LFS twice, and the results are somewhat widely different than what I am getting when I test at my house for example:
Saturday, 18 June 2022 LFS results
They use one of those Aqua Spin testers.
PH 7.9
ALK 208 which I was tild converts to 11.3 DKH
Phos .3
Cal 484
MG 1554
Ammonia 0.0
Nitrite 0.1
Nitrate 22


My Test results same day an hour after the LFS tested

PH 8.14 Seneye
ALK 13.1 Hanna
Phos .43 Hanna
Cal 480.0 Red Sea
MG 1600 Red Sea
Nitrite (I dont test for)
Nitrate 11.7 Hanna

So I have been testing twice per weeks for about 3 weeks, so I have good trend patterns and they are accurate with what I have been doing such as adding calcium, alk, and MG. The result are commensurate with this activity. Since I have reduced what I am dosing I expect to see the trend to flatten rather than incline at the rate that I was previously seeing.

Currently there are no corals in the tank to uptake the calc and alk.