hannah phos meter and readings

[poknsnok]

I got my Hannah phos meter and got a reading of .0144. does anyone else have this meter and what are your readings?

[slojmn]

That seems odd, my Hanna Phosphate Meter only goes out two places to the right, is that 100ths?? when I use it. I get readings like 0.03, which is what I got today. Are you sure it was not reading 0.144, still though that goes out 1000ths, to far compared to mine. Hmmmmm, odd

[cidory]

0.03 here too

[poknsnok]

if you read the manual it is calibrated to read at 68f (20c).. directions say to divide by 2 at 86f (30c).. IE a reading of.03 at 68f would be .015 at 86f... at 80 it would be .0165... mine is .02 at 80 which gives me .0144 adjusted to temperature.. below is taken from the manual and explained by a local reef store owner

All the reaction times reported in this manual are referred to 20C(68F). As a general rule of thumb, they should be doubled at 10C(50F) and halved at 30C(86F).”



Simple percentage of increase or decrease.



18 degrees F = +/- 50%



My temp is 79F. (11F= ~31%)



The reading is 0.08. (31% = 0.0248)

taken from tha manual and from the explanation of a very knowledgeable LFS here in Tampa

[GTR]

That's interesting but I'm not sure the interpretation is correct. It says adjust the reaction time and not the reading delivered.


SteveU

[poknsnok]

the reaction time is 3 minutes as timed on the meter. I understand what you are saying but the meter has a non adjustable timer set at 3 minutes and counts down from there. I dont see where the countown can be stopped at 1.5 minutes and a reading taken. so i believe the interpretation is correct because of that..I will read the manual later and verify.

[GTR]

The only reference of time in the manual that I recall is the timed read. That may be the reason they have the direct reading option and you supply your own alarm clock. :lol:

I talked with Hanna today and though I did talk to a rep he's going to pass on my question to get some clearification on procedure when the test sample is 78°F.

I've had periods of time were I get <.02 results which by this formula would mean actual level would be .0062. Looking at the tank, I think not. :)

SteveU

[chadfarmer]

i am down to .02

so that means .01

[icliao]

Would any one recommand me to invest on this Hannah Phosphate Meter?

[poknsnok]

mine is at .02 also and adjusted to temp it is .0144. there is a read now option on the meter. so I will test again and use that option and test at around 2 minutes to see what we get. I would suggest the meter since on Salifert I get no reading at all for Phos...

[jmcmahon66]

poknsnok- I am a little confused as to your actual reading on the meter. Is your uncorrected reading 0.08 or 0.02? Others have reported the instrument reading in their replies. My Hanna has an instrument reading of 0.03. I was unaware of a correction factor, and have always used the instrument reading for my PO4 level determination. If you wish to compare your readings to others (as you mentioned in the start of this thread), you have your answers. As you know, the meter is somewhat sensitve to other factors like fingerprints, amount of reagent used, micorbubbles, and undissolved reagent so consistancy is the key to taking a good reading. It took me several times to get consistant results.

[poknsnok]

the reading on the meter was .02... adjusted to 81 degrees s/be .0144... I cleaned as best I can the vial. tried to keep micr's to a minimum. I will test a few times this weekend to see what kind of spread I get... If the manual is followed you need to adjust for temp. whether you adhust the time of the test or the reading I am not sure. Im going to call Hannah and see. The manual states that the perscribed times were at 68f and to be corrected at other temps.

[falcon41176]

where did you guys buy your meters at

[poknsnok]

bestlabdeals.com

[VCoo71]

the instructions sheet that i have says all readings are reffered to at 68 degrees and should doubbled at 50 degrees and should be halved at 86 degrees

charlie

[poknsnok]

it seems to me it says all times as in testing times should be adjusted. it is confusing

[GTR]

<a href=showthread.php?s=&postid=7829327#post7829327 target=_blank>Originally posted</a> by VCoo71
the instructions sheet that i have says all readings are reffered to at 68 degrees and should doubbled at 50 degrees and should be halved at 86 degrees

charlie

<a href=showthread.php?s=&postid=7818572#post7818572 target=_blank>Originally posted</a> by poknsnok
All the reaction times reported in this manual are referred to 20C(68F). As a general rule of thumb, they should be doubled at 10C(50F) and halved at 30C(86F).”


Doesn't say readings, it says reaction times. I'll have to look back through my emails and find the address for the person that helped me with some issues a year or so ago. They replied right away whereas the guy I talked to a couple days ago I guess forgot about me. :(

SteveU

[poknsnok]

was the guy you conversed with from Hannah?? .. the meter does have a read now option. so I will hand time my next test and read at 2 minutes (approx)

[GTR]

Yes, I talked with Hanna USA on the east coast but he said he was more on the electronics end of this and couldn't really help with the question and was to pass it along for clearification.

Jessica

[manderx]

it's time reaction time, not the reading. i did a test on mine a few times where i hit 'read now' every 15 seconds after a minute and saw no change in the reading, so i don't bother worrying about correcting for temp. but don't take my word for it, try it yourself.

[GTR]

If I do a "read now" and then a "timed read" the timed read will most often be lower I'd guess due to turbidity.

Really though when it comes right down to it I'm just looking for trends and not an absolute value anyway. As long as I'm consistent in the method I'll get that.

SteveU

SteveU

[manderx]

yeah, mix the powder and drop the tube in the hole like normal. wait 1 minute. then hit 'read now' every 15 seconds and write down what it says each time. post your results. someone is borrowing mine so i can't do one too now.