Phosphate vs phosphorus Hanna checker

[RC Reefer 5184]

I have both checkers and on my last tank check I got
Hanna checker phosphate LR read - 0
Hanna checker phosphorus ULR read - 13 ppb (which converted to .04 ppm)
can someone explain what the difference is between the two and if the .04 is what I should be trying to keep or upping the phosphate number.
Looking to get my nitrates and phosphates where I need them. Nitrates where zero per Hanna checker and I have been dosing some ME coral nitrates to raise it some.

 

[sunken3]

there is a more scientific answer (that will likely come), but the phosphorus ulr will be more precise in the low range (where you are at). if you check the hanna specs, the precision on the phosphate is +/- .04 ppm, the phosphorus is +/- 5ppb - quite a big difference. that said your phosphate checker and phosphorus, agree to each other taking the precision into account.

 

[sunken3]

also, what are you keeping in your tank? many things like a little nitrate... (<10ppm). phosphate (<0.1ppm)... some folks will say less than half of that is desired

 

[RC Reefer 5184]

It is a mixed reef but 90% lps and softies.

 

[RC Reefer 5184]

That’s why I was trying to get nitrates up and was dosing nitrate. I guess I would be ok with phosphate at .04 to .08 if I can get nitrates to register. Just wanted to see if I should shut protein skimmer off for awhile to help raise them. Or if just over feed for awhile and wait

 

[sunken3]

what are you testing your nitrates with?

 

[sunken3]

i would stick to the Phosphorus checker at this point

 

[sunken3]

my nitrates sit around 3-5ppm .. i can't get them lower (at least not without doing something different) - but i have a lot of fish, and big fish

 

[RC Reefer 5184]

I just got the hanna nitrate checker. I was using a Red Sea test kit before that.

 

[RC Reefer 5184]

Well I have a 320 gallon tank with about 15 fish. And can’t seem to nitrates to register

 

[Randy Holmes-Farley]

FWIW, the two results that the OP got are not inconsistent since the phosphate checker has a +/- 0.04 ppm range of uncertainty, and the phosphorus checker has a range of +/- 0.015 ppm.

Thus even if both are working perfectly according to spec (and I would not assume they are), the actual value could be anywhere from 0.025 ppm to 0.04 ppm phosphate and both would be reading right.

 

[sunken3]

Well I have a 320 gallon tank with about 15 fish. And can’t seem to nitrates to register

i have 21 fish in a 245 (about 350 total) - but my nitrates sit around 3-5 (on nyos) - the hannah low checker says they are over 5 (so i stopped using it for now).

 

[Aquaturbo911]

FWIW, the two results that the OP got are not inconsistent since the phosphate checker has a +/- 0.04 ppm range of uncertainty, and the phosphorus checker has a range of +/- 0.015 ppm.

Thus even if both are working perfectly according to spec (and I would not assume they are), the actual value could be anywhere from 0.025 ppm to 0.04 ppm phosphate and both would be reading right.

Hi Randy,

It's probably too late to let you know but I mention it for people who might be looking for the correct info.
What you measured on both checkers are correct because there is a conversion between them.

FWIW, the two results that the OP got are not inconsistent since the phosphate checker has a +/- 0.04 ppm range of uncertainty, and the phosphorus checker has a range of +/- 0.015 ppm.

Thus even if both are working perfectly according to spec (and I would not assume they are), the actual value could be anywhere from 0.025 ppm to 0.04 ppm phosphate and both would be reading right.

That's because of the conversion number between two measurements.
Hanna website has this info but I took a screen shot of it. Phosphate checker result needs to be multiplied by 0.3261 to get phosphorus equivalent measurement. That is true for the uncertainty number. 0.04 × 0.3261 = ~0.014

 

[Randy Holmes-Farley]

Hi Randy,

It's probably too late to let you know but I mention it for people who might be looking for the correct info.
What you measured on both checkers are correct because there is a conversion between them.

That's because of the conversion number between two measurements.
Hanna website has this info but I took a screen shot of it. Phosphate checker result needs to be multiplied by 0.3261 to get phosphorus equivalent measurement. That is true for the uncertainty number. 0.04 × 0.3261 = ~0.014

I’m not sure who you are making the comment for, but I did not make any measurements and posted the converted uncertainties above .