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PO4 question with Hanna checker


The ReefBox
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So has anyone ever tested po4 with Hanna checker and after getting number then later checked again with same samples and got totally different numbers?

 

I tested because of light brown hazing that I get daily on the inside of my tank walls. I can clean it and the very next day start to notice light brown algae. Which lead me to test. The first test I received a result of .11 I let the sample sit for about half hour and tested again using same samples (no new water or reagent) and result was .00

 

Just checking what others think as I don't believe this second test would be accurate based on the brown algae dusting I get everyday

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I have burned through many refills on that test, but never tried that particular experiment.  

 

The test is tricky, but you get a cadence for it.  I do the following.

 

Turn on the checker

Fill the bottle

Wipe it very carefully clean

Put it in checker, 10mls facing directly forward

Push the button

While hanna is reading, open the reagent pack, I cut corner to corner and then squeeze it to make a 'funnel' for pouring it out.

Take out the bottle.

Pour in the reagent, getting as much in as I can.

Shake it hard until all white dots are gone.

Put back in hanna

Press and hold button (people sometimes miss this).  Pressing and holding starts a three minute timer after which the sample is read.

Set a timer on phone so I don't forget to read value in three minutes.

Read the result and log it.

 

Hope that helps somehow...

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I have burned through many refills on that test, but never tried that particular experiment.  

 

The test is tricky, but you get a cadence for it.  I do the following.

 

Turn on the checker

Fill the bottle

Wipe it very carefully clean

Put it in checker, 10mls facing directly forward

Push the button

While hanna is reading, open the reagent pack, I cut corner to corner and then squeeze it to make a 'funnel' for pouring it out.

Take out the bottle.

Pour in the reagent, getting as much in as I can.

Shake it hard until all white dots are gone.

Put back in hanna

Press and hold button (people sometimes miss this).  Pressing and holding starts a three minute timer after which the sample is read.

Set a timer on phone so I don't forget to read value in three minutes.

Read the result and log it.

 

Hope that helps somehow...

So did you change gfo or how did you verify was accurate? Did brown algae go away

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For me, after trying many things (po4x4,gfo,phosguard, lanathum chloride), what ultimately worked was removing my sand bed and some of my live rock.  Apparently the sand was leaching phosphates pretty bad.  I still have about half the sand, I stopped removing it after GFO could finally keep phosphate at 0.  Before the sand was gone, GFO could not touch it.

 

I barely miss it, and there is some in the back half of the tank for the sand lovers like the diamond goby.

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I am interested to hear more about that.

 

Not much to say really, we've tested them back to back over and over against the lab grade version and the checker was always off, sometimes a little, sometimes a whole lot. Much farther than the +/- .04 hanna claims.

 

A good option if you don't want to shell out the $500 for the Hanna lab grade unit is the Hach PO-19 kit, this is the same kit Randy Holmes Farley uses.

 

http://www.hach.com/phosphorus-orthophosphate-reactive-test-kit-model-po-19/product%3Fid%3D7640214958

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That is troubling to hear.

 

I remember researching this before settling on Hanna for phosphate.

 

Dana Riddle did a review on Advanced Aquarist and claims:

 

The results generated by the inexpensive Hanna Checker are remarkably close to those reported by a $3,500 spectrometer.

 

Article Here:

 

http://www.advancedaquarist.com/2011/8/review

 
 
I don't work in a lab for a living, but it is a compelling article that claims Hanna Phosphate checker is very accurate.
 
So don't throw out your checkers just yet people...
Edited by theclark
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That is troubling to hear.

 

I remember researching this before settling on Hanna for phosphate.

 

Dana Riddle did a review on Advanced Aquarist and claims:

 

The results generated by the inexpensive Hanna Checker are remarkably close to those reported by a $3,500 spectrometer.

 

Article Here:

 

http://www.advancedaquarist.com/2011/8/review

 
 
I don't work in a lab for a living, but it is a compelling article that claims Hanna Phosphate checker is very accurate.
 
So don't throw out your checkers just yet people...

 

 

 

I remember seeing the article, it's what made me buy one! Sadly they just don't seem to live up to the hype.

 

Over the last couple of years I've really quit testing my tanks, now I'm not saying everybody go throw your test kits out but I've just learned over the many years of keeping reef tanks to see what my tank likes and doesn't like and just adjust accordingly. I know when my P04 is too high or too low.

 

If I can't figure it out I just grab the lab grade Hanna at Upscales and run some water through it if I'm really feeling stumped.

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This is interesting, I have been thinking allot about this discussion.  By chance I was reading something else and stumbled across a phosphate video from macna.

 

Too funny, this  video among other things exactly asks the question that you did Brian at around 15:05 (inconsistent results as ArsonMfg pointed out).

 

He also talks about Hanna (bad precision and good).

 

Sure seems like a perfect fit for this intriguing discussion.

 

I found it to be thought provoking, but have no plans to raise my nitrates to 100 and phosphates 1o 1.85, or let my alk swing from 7 to 15, not just yet.

 

I also tend to think this guy may get a little sloppy in his testing, if you watch the whole video you know what I mean.

 

Enjoy if you haven't seen it!

 

 

http://reefbuilders.com/2015/03/10/rich-ross-focuses-phosphate-macna-2014-speaker-video/

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My green egg was crap. I got the same results Brian has, different tests, different numbers, I'd just keep testing until I got a number I was happy with as in;

 

.18 to high test again...

 

.14 getting better test again....

 

.10 still not what I was hoping for test again....

 

.05 ah that's what I thought-Love my hanna tester :clap:

 

Not sure whose payroll that Riddle guy was on or maybe he had an accurate one, Im sure they all aren't crap but mine was and I tried at least 8 different reagent packets (I buy in bulk what canI say)

 

I invested in an ultra low reader with a friend but I've never let him use it-In guess it's time to buy his half out

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I have the ultra low phosphorous checker and purposely never run the test back to back cause I don't want the headache of trying to decide which number to take :).

 

As far as why the test would first say one thing and then 30 minutes later say something lower, I'm not sure. I will say that I have heard over and over not to leave the reagent in the cuvette because it can stain the glass and throw off your results. However, I would expect that to make the reading go up not down, but I'm not sure. 

 

Anyway, I just thought I would throw that out there. 

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I have the ultra low phosphorous checker and purposely never run the test back to back cause I don't want the headache of trying to decide which number to take :).

 

As far as why the test would first say one thing and then 30 minutes later say something lower, I'm not sure. I will say that I have heard over and over not to leave the reagent in the cuvette because it can stain the glass and throw off your results. However, I would expect that to make the reading go up not down, but I'm not sure. 

 

Anyway, I just thought I would throw that out there. 

 

yep, I agree, there are some reasonable things to do to ensure precision and repeatable results.  What you suggested is in that article... good stuff

 

 

Sampling Procedures

"Garbage in; Garbage out" is a saying applicable to results generated when improper sampling procedures are in place. Use reasonable care when gathering samples for analyses. It is recommended that the vials (cuvettes) supplied by Hanna are used when sampling to avoid contamination.

Alkalinity: Analyze immediately or fix sample by refrigerating at 4°C (39.2°F) for up to 24 hours. Bring to room temperature before analysis. If the sample is gathered in a container other than Hanna's cuvette, either clean plastic or glass is OK, and it should be completely filled to avoid prolonged exposure to any air trapped in the bottle. Filter if the sample contains excessive suspended particles.

Phosphate: Analyze immediately. Use the Hanna 10 milliliter cuvette to draw the sample if possible. If not possible, use clean plastic or glass containers - they should be scrupulously clean - preferable acid-washed with 1:1 hydrochloric acid and rinsed with de-ionized water. To fix the sample, exclude particulate matter via filtration and refrigerate at 4°C (or 39.2°F). Maximum holding time is 48 hours.

Treat the cuvettes with respect, and keep them clean and free of scratches. Don't allow the treated samples to remain in the cuvettes any longer than necessary as the chemicals might stain the glass. If the vials do become stained, gently clean them with paper used for sensitive applications (such as that used to clean camera lenses). In extreme cases, a dilute bleach solution may be required to remove the stains. Some hobbyists keep the vials filled with deionized water between uses to prevent spotting within them.

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My green egg was crap. I got the same results Brian has, different tests, different numbers, I'd just keep testing until I got a number I was happy with as in;

 

.18 to high test again...

 

.14 getting better test again....

 

.10 still not what I was hoping for test again....

 

.05 ah that's what I thought-Love my hanna tester :clap:

 

Not sure whose payroll that Riddle guy was on or maybe he had an accurate one, Im sure they all aren't crap but mine was and I tried at least 8 different reagent packets (I buy in bulk what canI say)

 

I invested in an ultra low reader with a friend but I've never let him use it-In guess it's time to buy his half out

 

That is so funny, exactly what the guy talks about in the MACNA video.  If you get a good test, yay!  If not, retest, retest, retest til you like the numbers.

 

I am lucky and have a great green egg.  When I get a bad number, test again, I get another bad number that is close.

 

To give the NRA slogan a Hanna spin...

 

I'll give you my green egg when you pry it from my cold, dead hands

 

Or 45 bucks, whatever it costs to get a new one :rolleyes: 

Edited by theclark
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Well I just added a cup new hicap GFO so I guess we will see if the brown algae haze diminishes over the next few days pulling a new reading as we speak to compare it to as well

 

Just be careful not to strip your system too fast, you'll have a lot bigger problems than the brown algae!

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