Hanna Phosphorus Checker Inconsistent

[Scurvy]

Seems like you're making progress towards more consistent readings. I'll add to use a soft cloth Vs. paper towels to wipe down the vials. They're better at fingerprints/oils.

 

[DarkSky]

I think the biggest variance you're going to introduce is with the packets of powder. I really wish they'd make a liquid reagent version of the test, like the Alk one. It'd be so much easier / consistent.

 

[LuizW13]

That's odd, i used the same one as you and get very consistent results. Every time i use the Hannah checker for Phosphorous and Alk, i do three back to back readings and will use the average. The phosphorous almost always has the same ready during the 3 tests.

Also, does anyone why they still use those stupid little packets? Not sure why that would be better than a little tube and spoon. ;Bored

 

[terri_ann]

Get a standard...use it prior to testing to see that it falls within range. I use a small funnel purchased from Bed, Bath and Beyond...cut the small end above the 10mm mark so the powder will not get wet (prevent the tip from touching the sample water.) Keep vials in vinegar when not in use to ensure clean vial...rinse with sample water, dry exterior with no scratches, finger marks,etc. Place a mark on cuvette and tester...line up marks for every test. I use the same 10ml syringe for every test(no bubbles/air pockets in the syringe)...no I do not use the line on the cuvette. The syringe is more consistent. Use timer for mixing...Hanna says total test time for accurate reading is 5 minutes... Reagent should not be expired. New(er) reagent dissolves pretty quickly...less than 2 minutes. "Microbubbles can be removed at any point in procedure by gently tapping cuvette on bottom(side of cuvette if needed) on a table/counter." At 1 min 50 sec, stop inverting cuvette and place in tester with both lines/marks lined up. Close lid, press and hold until 3:00 appears...release. At end of 3 minutes, take #ppb *3.066, then divide by 1000= #ppm If my first test seems "off", I will test again for me having made an error. If test the same water sample twice, range should fall within error for each sample.

Look for trend(s). If test results start to rise and the feeding has been the same as well as maintenance (WC's, etc), GFO is beginning to become ineffective. If large increase in test result, phosphorus/phosphates are leaching....GFO past useful life. HTH!

 

[Servillius]

So I've been having inconsistent results with the Hanna Phosphorus checker. I've been searching and searching and I see this is a very common problem. I've been trying to take notes on what everyone says to help improve consistency. It's not working for me and it's so frustrating! What am I missing?

I just completed 2 back to back tests with the same cuvette. First test came back at 63ppb and the second test came back with 133ppb. I used a turkey baster to put water into a small cup. Both test were used from the water in the cup. I strained the water through filter floss to reduce particles. Even after doing this there were small amounts of particles floating in the glass. Is this an issue and how can I fix it?

1. Put gloves on
2. Srain water through filter floss into small cup.
3. Use turkey baster to fill cuvette with exactly 10ml of water
4. Cut open reagent on two sides to form a funnel to get ALL of the reagent into the cuvette.
5. Wipe cuvette with paper towel so there are no smudges.
6. Place in hanna checker with 10ml label facing me and hit the button.
7. Remove cuvette and set time. Place reagent in cuvette and invert for 2 minutes.
8. Wipe cuvette of any smudges
9. Place into checker with 10ml facing towards me and hold button until 3 minute timer comes on.

Here’s the problem. If you do not mix for the full two minutes, your results will be unreliable.

My process, using a timer like the one on your phone, follows;

1. Cut open and set aside the reagent packet.
2. Turn on device (C1)
3. Fill cuvette, clean and dry.
4. Zero out with empty cuvette (C2).
5. Quickly open, add reagent, then start 2 minute timer.
6. Don’t shake, but keep turning upside down then right side up for the full two minutes stopping only once to whipe down cuvette with cloth.
7. At two mins, insert into machine, close, and press and hold until 3 mins shows.
8. Set a three minute timer so I don’t forget to check the result after I invariably wander away.

I’ve run the experiment and taking less than two minutes makes the result unpredictable. You have to shake for the full two minutes. Because the machine shuts off at 3 minutes, that can be a hassle.

 

[lion king]

Unless you got a faulty unit, you will not get more accurate results from anything else, the hanna checkers are the gold standard. Most inconsistencies are user error, and with this checker, many times it's about getting all the reagents into the vial. I use these to help with adding reagents to my hanna vials. https://www.amazon.com/gp/product/B009CZEQ36/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[KrisReef]

Lots of good advice given so far. The only one thing missing from the list (rinse the test bottle with DI, wipe it spotlessly clean, align the vial in the test hole, carefully empty the blind sachet of all hidden contents, shake but don't stir any bubbles for a full 119 seconds), is the most important piece of advice, which is to pray. I find that asking for divine intervention makes me feel better about the possibilities of accurate results.

I also own a set of the Hanna ULR standards, and have decided that machine and ambient air temperature may also have an impact on the test results. The best advice additional practical advice is to watch the glass inside the tank for algae, and calibrate the Hanna for ballpark estimates of the actual P in your system using those observations.

 

[blackflme]

Problem SOLVED!!! I finally contacted Hanna and made 4 recommended adjustments.

1. Straining was unnecessary (no surprise there)
2. Use a syringe instead of a turkey baster. I don't really think this has much to do with it because if I filled the syringe to 10ml it would over or under fill the cuvette. I could get the turkey baster to be right on target.
3. Make sure to fill water to the 10ml mark and make sure the meniscus is touching the line. So the water should appear to be over the line. Google "meniscus water" and you will see pictures.
4. Rinse the cuvette in tank water. I think this was my real issue. I just dunked the entire cuvette in the tank and emptied 2-3 times.

These test were all done today.

Test Results before adjustments
Test 1: 200ppb(max reading)
Test 2: 122ppb
Test 3: 200ppb(max reading)

Test Results after adjustments
Test 1: 0ppb
Test 2: 2ppb
Test 3: 1ppb

I'm so relieved. Hopefully this helps others.

 

[blackflme]

Lots of good advice given so far. The only one thing missing from the list (rinse the test bottle with DI, wipe it spotlessly clean, align the vial in the test hole, carefully empty the blind sachet of all hidden contents, shake but don't stir any bubbles for a full 119 seconds), is the most important piece of advice, which is to pray. I find that asking for divine intervention makes me feel better about the possibilities of accurate results.

I also own a set of the Hanna ULR standards, and have decided that machine and ambient air temperature may also have an impact on the test results. The best advice additional practical advice is to watch the glass inside the tank for algae, and calibrate the Hanna for ballpark estimates of the actual P in your system using those observations.

What is DI? Maybe this is pretty close to rinsing with tank water?

 

[Mako61]

Glad to hear you are getting consistent results!

I use a cheap plastic pipette to fill my vial. I got like a 100 of them for a few bucks. I like using them better that a syringe because of bubbles.
With a little practice and the pipette -- I can get some water and put it in the vial without creating any bubbles.
I keep the tip of the pipette under water and dont use all the water each time I add.
Its very fast and very easy once you get the hang of it.

I also rinse my pipette and vial before each test. I waste very little water like 3ml.
I rinse my vial after each use and dry the inside before storage.

After reading your thread I did a test of freshly mixed water and got zero as expected. My tank seems to always be 40ppb. ( a little higher than I like )

 

[KrisReef]

What is DI? Maybe this is pretty close to rinsing with tank water?

DI= Deionized water. Ultra low concentrations help dissolve/remove sediments that build up inside the bottle, and they don't add minerals deposits at the same time. Just another way to keep the glass as clean as possible. If you go to a car wash, DI is what is sprayed on your car to provide a "spot free rinse."

 

[blackflme]

I don't seem to have a problem with bubbles either way I do it. I also rinse me cuvette with tap water after each use. I dont have a good way to dry the inside, so I just put it back in the case with the cap off. The turkey baster I use could be an issue only because I feed my corals with it. I do rinse the baster several times after using it though.

Because my test were coming back so high I just changed the GFO that was only like 3 weeks old. The 0-2ppb seems to be too low than most people like which kinda sucks. I'm just now coming back from an algae problem I had. I was overfeeding big time for a month lol. There is still a lot of algae growth, but its almost where I want it. I still have to wipe the glass every 2-3 days though.

 

[blackflme]

DI= Deionized water. Ultra low concentrations help dissolve/remove sediments that build up inside the bottle, and they don't add minerals deposits at the same time. Just another way to keep the glass as clean as possible. If you go to a car wash, DI is what is sprayed on your car to provide a "spot free rinse."

Ok, thats what I was thinking. I've only heard people say RODI so thats what through me off. I'm sure that would have definitely fixed it. I didn't see your comment until today. I had thought about rinsing with RODI but I keep it in 5g jugs and its pretty hard to get small amounts of RODI water out. So I stick to rinsing with tap water for my refractometer and cuvettes.

 

[dankreef]

That's odd, i used the same one as you and get very consistent results. Every time i use the Hannah checker for Phosphorous and Alk, i do three back to back readings and will use the average. The phosphorous almost always has the same ready during the 3 tests.

Also, does anyone why they still use those stupid little packets? Not sure why that would be better than a little tube and spoon. ;Bored

Dude honestly someone give them the memo this is the worst way to deliver the reagent. #burnpaperpacketidea

 

[living_tribunal]

Problem SOLVED!!! I finally contacted Hanna and made 4 recommended adjustments.

1. Straining was unnecessary (no surprise there)
2. Use a syringe instead of a turkey baster. I don't really think this has much to do with it because if I filled the syringe to 10ml it would over or under fill the cuvette. I could get the turkey baster to be right on target.
3. Make sure to fill water to the 10ml mark and make sure the meniscus is touching the line. So the water should appear to be over the line. Google "meniscus water" and you will see pictures.
4. Rinse the cuvette in tank water. I think this was my real issue. I just dunked the entire cuvette in the tank and emptied 2-3 times.

These test were all done today.

Test Results before adjustments
Test 1: 200ppb(max reading)
Test 2: 122ppb
Test 3: 200ppb(max reading)

Test Results after adjustments
Test 1: 0ppb
Test 2: 2ppb
Test 3: 1ppb

I'm so relieved. Hopefully this helps others.

I’m currently having the same issue. It’s been all over the place for me today.

Can you elaborate on 4?

I’m confused by why you would need to put the cuvette in tank water. I just rinse mine with tap after I’m done.

 

[KrisReef]

I’m currently having the same issue. It’s been all over the place for me today.

Can you elaborate on 4?

I’m confused by why you would need to put the cuvette in tank water. I just rinse mine with tap after I’m done.

@living_tribunal
The meter gives reliable results if
1. use a syringe to measure 10ml into the test cuvette
2. Wipe the outside clean with a paper towel or cry cloth to remove smudges from the glass.
3. Start the meter, add the clean sample cuvette. I align the 10ml mark with the front of the meter.
4. When it asks for the second sample, remove the cuvette and add all of the envelope contents. Start a stop watch and shake for the full 2 minutes.
5. Put the shaken sample back into the meter being careful to align the 10ml mark again with the front of the meter.
6. Hold the test button down until it starts the 3 minute timer.

The test reagent colors are at there peak for correct readings at 5 minutes in the cuvette, so the two minutes of shaking + 3 minutes of timer give the most accurate results.

The repeated alignment of the cuvette helps prevent errors from light deflection as the test is performed.

The old #4 = Rinse the cuvette with Deionized water after the test is finished. I rinse my cuvettes and then fill them with DI before I store them. It helps prevent mineral build-up on the glass which can also impact test results.

The above information was gleaned from others on here who have posted about Hanna Checkers and getting correct results. IHTH.

 

[living_tribunal]

@living_tribunal
The meter gives reliable results if
1. use a syringe to measure 10ml into the test cuvette
2. Wipe the outside clean with a paper towel or cry cloth to remove smudges from the glass.
3. Start the meter, add the clean sample cuvette. I align the 10ml mark with the front of the meter.
4. When it asks for the second sample, remove the cuvette and add all of the envelope contents. Start a stop watch and shake for the full 2 minutes.
5. Put the shaken sample back into the meter being careful to align the 10ml mark again with the front of the meter.
6. Hold the test button down until it starts the 3 minute timer.

The test reagent colors are at there peak for correct readings at 5 minutes in the cuvette, so the two minutes of shaking + 3 minutes of timer give the most accurate results.

The repeated alignment of the cuvette helps prevent errors from light deflection as the test is performed.

The old #4 = Rinse the cuvette with Deionized water after the test is finished. I rinse my cuvettes and then fill them with DI before I store them. It helps prevent mineral build-up on the glass which can also impact test results.

The above information was gleaned from others on here who have posted about Hanna Checkers and getting correct results. IHTH.

I get all of that but what I don’t get is why/when he is filling the cuvette with tank water? The only time the cuvette comes into contact with tank water for me is when I’m syringing the water into the cuvette. I’m confused what else we’re supposed to do with tank water.

I certainly don’t want regent in my tank...

Did he make a typo and meant to rinse the cuvette with di/tap water after test to clean?

 

[KrisReef]

I get all of that but what I don’t get is why/when he is filling the cuvette with tank water? The only time the cuvette comes into contact with tank water for me is when I’m syringing the water into the cuvette. I’m confused what else we’re supposed to do with tank water.

I certainly don’t want regent in my tank...

Did he make a typo and meant to rinse the cuvette with di/tap water after test to clean?

I think that you are correct about the washing or rinsing with tap water probably auto corrected to tank, but best practice is to rinse and store with DI.

 

[living_tribunal]

I think that you are correct about the washing or rinsing with tap water probably auto corrected to tank, but best practice is to rinse and store with DI.

Definitely.

I think my issue was not lining up the meniscus as well as shaking too aggressively. I just got a real result back and am going to verify a few times. If it’s true, I need to dose some phosphate lol

 

[KrisReef]

Definitely.

I think my issue was not lining up the meniscus as well as shaking too aggressively. I just got a real result back and am going to verify a few times. If it’s true, I need to dose some phosphate lol

I bought some 10mm syringes at the hardware store and have found that those are much easier to use for filling the cuvette with the same amount every time. It's an extra step and I wash the syringe with DI afterward but it's easier for me than trying to see the meniscus.

As far as shaking, I shake the bottle for the first 20 seconds and then upend it repeatedly for the remainder of the 2 minutes. I will check and swirl it a bit to remove any bubbles at about 1:40 and then slide it carefully into the meter and push the button at 2 minutes.

I really like the Dkh meter because it doesn't take so long!