Test Kits

[dwair]

So I have Hanna Checkers for Alk, Calc, Phosphate, Salifert for Mag, and Red Sea for PH/Nitrates

Anyone else notice how these test kits are so Wildly different? The hanna checker I use for Alk, I tested it today, came up 7.1, this didn't really make much since, so tested again, came up 9.0, tested again 9.8. This makes absolutely NO sense. How do I get 3 different readings, all clean vials, the test isn't exactly difficult so I know I'm doing it right. Why is this a thing?

 

[andrewey]

When you say you are doing it right, are you positive? I don't mean that you are missing steps or not following the directions, just that there are several steps where the user can influence the results a lot. Before I got better at my technique, I could get answers that were up to 1dkh different from each other. I'm not saying that's what's happening here, just that it's something I wouldn't assume plays no part in what's going on.

That being said, I would also ensure you're testing kits are the right type for the right unit, are not expired, and aren't close to being expired.

The last cause is also that some batches seem to not be great. I wouldn't jump to this conclusion, but it's worth pointing out that some people that seem to struggle seem to have better luck with a different set of dry reagents. I would only move to this step if you determine the other steps aren't coming into play.

This assumes all samples were taken at roughly the same time.