HANNA P04 reagent - way different numers?

[IPT]

So i know home P04 testing isn't that accurate. None the less it would be nice to be in the ballpark, I have the HANNA P04 tester and the LR reagent and the Ultra Low. I was using the LR reagent and keep getting zero. I added some P04 additive to the tank and tested the water an hour later with the Ultra Low reagent - the unit said .04. My understanding is I need to multiply that by 3.06 then that by 1000, and then divide by 100 which gave me 1.22. I then immediately retested with the LR reagent and still got 0.0.

What gives? Are these that far off in accuracy? Does one have a better track record than another?

My tank is fine, but I can't seem to pull those nice blue tips on several pieces and I am wondering if I am low in P04.

 

[Justfebreezeit]

You have two different checkers? Or just different reagents?

I've never had a problem with the ulr checker and reagent. Nothing beyond reason anyways

 

[IPT]

FWIW I use the home made P04 solution but I diluted it so it's not full strength (I think it was 1.7G of Trisodium Phosphate per gallon RO/DI water). I would have expected the numbers to come up about .02 based on past testing experiences, but who knows how accurate that was/is.

 

[IPT]

You have two different checkers? Or just different reagents?

I've never had a problem with the ulr checker and reagent. Nothing beyond reason anyways

Same tester (the Green HANNA low range tester), different reagents LR and ULR.

You use the conversion formula with the ULR?

I guess I never used the conversion before...I might have just been taking the ULR reading of .04 for actually being .04, but if the Ultra Low requires that manipulation I might have had higher P04 than I thought. In hindsight I may have been using these reagents (each box say a month of tests per period) interchangeably month to month and not realizing the difference.

 

[martin.a]

Same tester, different reagents.

Mate, you need different tester for each reagent.

 

[IPT]

Mate, you need different tester for each reagent.

This could be. I need to do some research. I think than I read previously you could use either but might have to do the conversion. If anyone else can chime in on that please do. This is quite interesting.

I wonder how the ULR tester would compare to the LR tester side by side using the appropriate reagent in each? Anyone ever put these head to head?

 

[Randy Holmes-Farley Verified Community Expert]

So i know home P04 testing isn't that accurate. None the less it would be nice to be in the ballpark, I have the HANNA P04 tester and the LR reagent and the Ultra Low. I was using the LR reagent and keep getting zero. I added some P04 additive to the tank and tested the water an hour later with the Ultra Low reagent - the unit said .04. My understanding is I need to multiply that by 3.06 then that by 1000, and then divide by 100 which gave me 1.22. I then immediately retested with the LR reagent and still got 0.0.

What gives? Are these that far off in accuracy? Does one have a better track record than another?

My tank is fine, but I can't seem to pull those nice blue tips on several pieces and I am wondering if I am low in P04.

The math is not correct. The numbers also seem off.

A device reading in ppb phosphorous is multiplied by 3.06 to get ppb phosphate. Divide that by 1000 to get ppm phosphate.

A number of 0.04 is NOT ppb phosphorous, it is already ppm phosphate if you got the decimal point correct.

Can you show a picture of the Hanna that have 0.04?

 

[IPT]

Sure. I tested again using the ULR reagent and it came out at 0.0. It was a few hours so I guess the coral consumed it. I added some more Po4 solution and retested. Again using the ULR reagent in the unit I have and I pulled from the sump shortly after dosing to make sure some P04 was there.

 

[IPT]

Looking online and at the packets I have it appears both of what I have say "phosphate" (not "phosphorus", despite one being "Ultra Low" and one being "Low range".

Is it possible since they both measure "Phosphate" these are interchangeable in MY specific testing unit? That one reagent will just be more accurate than the other? Still I thought the LR should be able to test for 0.02 ppm?

 

[Justfebreezeit]

Yea obviously they must be different in some way to warrant still selling two different checkers.

Maybe chat with hanna.

 

[TokenReefer]

Hannah checkers have a model # that starts with "HI". The matching reagents have the same number on the packaging. My Phosphate ULR egg has it printed on the back fwiw

 

[Randy Holmes-Farley Verified Community Expert]

Looking online and at the packets I have it appears both of what I have say "phosphate" (not "phosphorus", despite one being "Ultra Low" and one being "Low range".

Is it possible since they both measure "Phosphate" these are interchangeable in MY specific testing unit? That one reagent will just be more accurate than the other? Still I thought the LR should be able to test for 0.02 ppm?

Both devices you picture report phosphate with no corrections needed.

 

[Randy Holmes-Farley Verified Community Expert]

The 713 and 774 reagent packs are reportedly not interchangeable.

 

[IPT]

This is all very interesting. I have been using the 713, usually with the proper reagent. Seems like this time I got the wrong one. However, upon reading more it seems to me 774 ULR Phosphate reader is the better of the two simply because it has a lower +/- amount and better accuracy at the typical .05 - .10 levels we most commonly strive for. I ordered the ULR tester. it will be interesting to see how the numbers and testing compares to what I have done in the past.