I don’t trust my Hannah test kit


Miami Reef

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Sep 8, 2017
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I’m using ULR phosphorus.

I preformed 2 tests back to back with same vial and I got .443 and .438 phosphates. My red sea phosphate test was in between .08 and .12

My tank appears to match the red sea test. Not that much algae except on the power heads.

My Hannah used to test 0.03 last week.

Anyway, I have 2 vials which I use in rotation (never both vials for the same test). I forgot to clean the last test so it’s been sitting in the vial. I rinsed the vial with soap and water. The other vial had vinegar in the vial if I remember correctly. I don't remember which vial I used, but I used the same vial twice and I got the same result.

Then I tested with a vial from my Hannah alk test kit which was used for the alk solution. I got a result of .40 which is slightly less.

I clean my vials by rinsing in tap water and closing the vials with a little tap that remained after me shaking the water out of the vial.

As far as test procedure, I preform is super accurately. I shake for 2 minutes. Use same vial for entire test. Tap bag to get powder out of edges and make a funnel. I wipe down the vials before each reading C reading. I am pretty confident in my ability to preforming the test, but I’m not confident in my ability of washing the vials.

One thing about Red Sea is that it’s pretty bullet proof. There’s no potential air bubbles or fingerprints that can stain results. I use the tap water to clean the Red Sea vials like with the Hannah checker. I also have more confidence in my ability to tell colors apart vs a colorimeter with no calibration.

So why don’t I just stick with the Red Sea? Because I like to use multiple test kits to ensure I’m not having a test kit inaccuracy. It prevents me from making a drastic change. For example, today I used hannah and not the Red Sea. If I didn’t double check the hannah twice, and then with the Red Sea, I would simply overdose my tank with chemicals which woukd starve my tank of essential nutrients.

That’s why I’m bothered inside. Maybe the hannah IS accurate and Red Sea isn’t? Uchh. How can I know?

For phosphate I use hannah and red sea
Alk: hannah and red sea
Cal, mag, nitrate, I use Red Sea and salifert

As you can see, I have different brands to double check results because I’m weird like that. So far I really like my Red Sea test kits the most. Except I feel like the nitrate test kit high range doesn’t work because the color turns a different shade altogether. It’s just an incentive for me to keep my nitrates lower so I can use the lower range
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Because your two tests with the Hanna were so close, I would say that test is either correct, or your vials were contaminated (which sounds possible). It does seem like you need better cleaning methods. Do you use a syringe to measure out the water? Don't use the line on the vial (some of my are good and some are way off).

Here's how I clean mine: Rinse outside and caps in tap water. Fill with tap water and dump about 5 times (do at least 3). Fill with RODI water and dump, rinse outside with RODI water, and let air dry upside down (I use a test tube rack). This does a good job with cleaning my cuvettes. A lot of people store them with RODI in them too.

I've never tried the Red Sea phosphate test but most just do not have the degree of specificity needed for low level phosphate. As for how your tank looks, if it looks good I wouldn't be too concerned, but my tank was overrun with algae and po4 was .05 LOL. So you can never tell how a tank will react anyway (it was at .05 before the algae developed, and after)

What is the best "cleaning product" or home recipe for cleaning reef tank equipment?

  • Water and scrubbing

    Votes: 11 13.9%
  • Citric Acid

    Votes: 39 49.4%
  • Vinegar

    Votes: 24 30.4%
  • Hydrogen peroxide

    Votes: 2 2.5%
  • Lemon Juice

    Votes: 0 0.0%
  • Other (please explain)

    Votes: 3 3.8%