Test kits and different readings

[Ste_J]

I have 2 test kits at the moment and both give different readings to the point where i'm not sure which is anywhere near right

Kit 1 is a Tetratest 5 in 1 strip test
results:

NITRATE = 10mg/l
NITRITE = 0mg/l
GH = 10d
KH = 3d
PH = between 7.6 & 8

Kit 2 ia an Aquarium pharmaceuticals

NITRATE = 0mg/l
NITRITE = 0mg/l
KH = 8d (8 drops before the liquid turns froblue to yellow?)
PH = 7.2
Amonia = 0mg/l

Co2 is equating to 15.143ppm (using 2 hagen units)

So the results are quite different and it's getting to the point where i don't know which is right, my lfs also use the aquariumpharm so their results would supposedly be the same as mine.

Any ideas?

The tank is a 3ft 28ukg being filtered by a eheim 2213 and lit by 3 tubes (1 20w lifeglo 2 18w arcadia originals) 12hr light cycle
temps around 26c
2 hagen Co2 units
live plants(a fair few which are doing nicely as they tend to bubble when the lights are on although the hair algae is starting to annoy me somewhat)

details of current stock are being discussed in another thread around here.

thanks for any advice that you offer as i would like to be able to test with confidence

 

[FishDan]

I don't know that there is really a satisfacorty answer. General thinking is that strips are usually less acurate than other test methods and are best for getting an "idea" of where levels are in your tank. Of course, liquid tests have other potential issues, the first being how does one REALLY ensure that the 5 (or however many needed for a particular test) drops are all uniform? Also, there is a concern with the potential for the test vials having residue inside from your previous testing. Either of these things can affect test results.

Maybe taking an average of both tests is a good way around the issues. I seriously doubt either test is too far off of the "actual" values, and either one would be good. Just remember, they are really only giving you an idea of about where your water parameters are at.

\Dan