Difference between Phosphorus & Phosphate

whitesquall

New member
Hey all,
I would like to buy one of the Hanna Checkers and have noticed that alot of reefers are buying either 736 for Phosphorus Ultra Low Range or 713 for Phosphate Low Range.

From what i've read Phosphorus & Phasphate seem to be different.

So my question is.... has anyone compared a test sample side by side between the two testers to see if there is a noticable difference in readings?

And which tester do I want to accurately check the level of Phosphate in my SPS reef tank?

-Alex.
 

Dr. Reef

Dr. Reef at ur service
RC Sponsor
different yes, phosphorus 736 is ultra low range and is much more accurate in low ranges.
regular phos test test range is 0 to 2.5ppm while phosphorus test range is 0 to 200 ppb.
ppb meaning is testing in much smaller unit making it more accurate in low range.
the only difference is part per million to parts per billion.
if u get 736 UL unit all u have to do is multiply the result with 3.066 then divide by 1000.
example:
12 x 3.066 = 36.792 / 1000 = .0367 ppm PO4
 

whitesquall

New member
OK... so then the preffered tester for our hobby is the 736 unit?

Also what would you say is an accurate Nitrate tester we could use for the reef tank?

-Alex.
 

kissman

New member
OK... so then the preffered tester for our hobby is the 736 unit?

Also what would you say is an accurate Nitrate tester we could use for the reef tank?

-Alex.

yes, i think it is the preffered tester too

Nitrate test kit I think the best is Red Sea Pro hands down better in the low range
 

hkgar

New member
+1 on the Red Sea Pro for nitrates. Teally like mine for the very low readings. I hop it is accurate lol.
 

jdegrasse

New member
Hanna makes testing equipment for many different industries (like agriculture, waste water testing, etc.) so choosing the right one can be confusing.

Both the 736 and 713 test for orthophosphate (which is a molecule that contains the element phosphorous) the same way (the classic ascorbic acid method). The only difference is the working concentration range.

The working range of the 736 model is relevant to our hobby.
 

bertoni

Premium Member
The 736 is a bit more accurate than the 713 in the low range, but not dramatically so. I think the difference is ±0.03 ppm vs ± 0.04 ppm. If your tanks generally are running towards the low end, the 736 should be fine.
 

jdegrasse

New member
The 736 is a bit more accurate than the 713 in the low range, but not dramatically so. I think the difference is ±0.03 ppm vs ± 0.04 ppm. If your tanks generally are running towards the low end, the 736 should be fine.

The 736 is +- 5 ppb
The 713 is +- 0.04 ppm
 

kenghmoob

New member
I wish I knew all this when I bought my Hanna phosphate checker which is the 713. Who would of known that we are testing Phosphorus too
 

bertoni

Premium Member
The 736 is +- 5 ppb
The 713 is +- 0.04 ppm
Yes, but the 736 reads ppb in phosphorus, so you need to multiple by 3, at least, so that's 0.015 ppm and then add 5% of the reading. That's actually a bit better than the original spec, I think.
 
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