Hanna phosphate ULR

[cactusreef]

So I have a Hanna phosphate tester. I have to do like 4 tests every time because I get different numbers ranging from .3 to .02. Is this normal? Has anyone else experienced this? I think I am following the directions….

Seems like a massive variation in tests done within 10 minutes of each other. I also am not testing and feeding and testing again. No changes to tank between tests. I almost put phosguard in with .3-.6 results but then also got .02 and .04 mixed in so idk what to do…

 

[edsbeaker]

In my experience, that is not normal. If it’s always been this way the checker could be defective or it sounds like it may be user error.

If you are getting all of the powder into the cuvette each time and shaking for 2 full minutes, two other possibilities come to mind.

First possibility, Are you being careful to make sure there are no bubbles on the walls of the cuvette before placing it into the checker?

Second possibility. Are you wiping off all the fingerprints and smudges on the outside of the cuvette before placing it into the checker? I’ve learned that it’s easier to only handle the cuvette with a towel.

 

[cactusreef]

I do make sure no bubbles and clean cuvette. Though I probably do not shake for full 2 mins. I suppose I could try shaking longer and see if that helps.

 

[Thumbster]

After 30 years off and on, I got the PO4 tester last week.
A couple things that I noticed in the directions, mix gently for two minutes. I think the directions say to tap or swirl to dissolve the powder and avoid bubbles. I was shaking fairly hard.
Another was wiping off the glass. I thought I was getting it good enough by cleaning it on my shirt, but I held it up towards the bright light of a window and I still noticed some smudges.
Whether either of these have much effect on the final reading, I don't know.
Also how are you cleaning out the cuvette after the tests? I would like to know myself. I have just been rinsing them out with RO water.

 

[slingfox]

I do make sure no bubbles and clean cuvette. Though I probably do not shake for full 2 mins. I suppose I could try shaking longer and see if that helps.

To get more consistent results you need to do the testing in a more repeatable way.

1) Get an auto micropipette from Amazon. This will allow you to draw 10ml from your tank more precisely

2) Get one of these to stir for 2 minutes more consistently: https://store.coralvue.com/smart-st...tY-Sw4gMQhROkHa-fuqu5YrO9ncCSAJrrmMSy-Oqi_ruU

To get it to work better there are a few of the reefing 3D printing vendors who set inserts so that the Hanna vial fits perfectly

3) When you add the mixed solution as the C2 sample, make sure you hold down the button on the Hanna checker so that it does its timed countdown before generating a reading

4) Rinse you testing vials with RODI at the end

 

[Mr. Mojo Rising]

I suggest to go to youtube and watch a video and make sure your doing the test correctly. IME the results are usually fairly similar.

 

[Randy Holmes-Farley Verified Community Expert]

It's not normal in my experience either.

 

[exnisstech]

Get one of these to stir for 2 minutes more consistently: https://store.coralvue.com/smart-st...tY-Sw4gMQhROkHa-fuqu5YrO9ncCSAJrrmMSy-Oqi_ruU

To get it to work better there are a few of the reefing 3D printing vendors who set inserts so that the Hanna vial fits perfectly

This is what I use. A piece of 3/4" pvc works perfect for holding the Hanna cuvettes and salifert test vials fit perfectly without the PVC.

I use a 10ml syringe to fill the cuvette. Not sure if you the OP are or not but i use a single cuvette for the entire test. I've heard of some people using two cuvettes, one for c1 and another for c2 which is not correct can cause inaccuracies.

 

[Zone1090]

I do make sure no bubbles and clean cuvette. Though I probably do not shake for full 2 mins. I suppose I could try shaking longer and see if that helps.

Turn your phone timer on. Do everything the same every time. Make sure you flush out curvette. I leave rodi water in mine till next time.

 

[EnterName]

I had this issue when the batteries where giving up even though the HannaChecker didn't show the low battery warning. Replace the batteries and try again.

If you just want to make sure the readings are stable you can use one vial with untreated tank water (C1) and another vial either reagent and tank water or some skimmer water or so (C2).

Simply do the reading multiple times and it should give numbers with low variance. This way you aren't wasting expensive reagent when testing multiple times.

 

[cactusreef]

I will try to be more careful with my tests and see if that helps. Thanks everyone. Maybe I need to replace batteries as well

 

[BryanM]

Consistency is key.

I like this idea of a 10ml syringe... I'm going to get one of those.

 

[commod0re]

1) Get an auto micropipette from Amazon. This will allow you to draw 10ml from your tank more precisely

Great tip! And they’re on sale right now. I just ordered a 1-10mL for taking samples and a 0.1-1mL for the alk test reagent

 

[King Neptune]

In addition to what has been said, make sure the cuvette is orientated the same way each time. I put a mark on my lid(s) to make this easier. As others have said - clean your cuvette with RODI water after use. Make sure to not get fingerprints on the cuvette (cotton gloves can work good when handling the cuvette during the test). Make sure to get all the powder out of the packet, etc.