Phosphate and the Hanna Phosphate checker

[KK's Reef]

I've been seeing conflicting info between the Hanna Phosphate checker the Phosphate ULR checker.

I have the regular one (not the ULR) and I wanted to know what the desirable range would be. For example, I saw a Youtube video where the hobbyist had the ULR checker and was happy with a test result of 0.03 ppm. Correct me if I'm wrong, but isn't 0.03 a desired result if you have the regular Phosphate checker?

 

[ahiggins]

The ultra low range is in ppbillion and the normal is ppmillion (roughly-see pic for conversion)
So for me, my ulr of 5 is actually 0.015 ppm which is a bit too low for my tank so I dose.

 

[Little c big D]

The .03 would be the PPM.

 

[ahiggins]

So if you have a 0.03 ppm on your normal ppm range, yes you’re roughly 0.03 ppm.

 

[KK's Reef]

The ultra low range is in ppbillion and the normal is ppmillion (roughly-see pic for conversion)
So for me, my ulr of 5 is actually 0.015 ppm which is a bit too low for my tank so I dose.

thank you, this chart is helpful!

 

[KK's Reef]

Thanks, guys.

Is a range of anything over 0.00 and below 0.10 generally considered as acceptable? Or, should it be around 0.03 to 0.05 ppm to keep the corals happy and nuisance algae at bay?

 

[ahiggins]

Yea they cite 0.03-0.05 a lot. I start to see cyano if I accidentally overdose though lol usually I see it if it’s <0.05 in my tank. But I don’t have any other algae to compete against it.

 

[Koigula]

As tanks mature they are more tolerant of elevated phosphates. For the first two years <0.1ppm phosphate is acceptable if you can somehow manage a reliable reading. I get different results from different test kits too.

 

[fushi]

I've been seeing conflicting info between the Hanna Phosphate checker the Phosphate ULR checker.

I have the regular one (not the ULR) and I wanted to know what the desirable range would be. For example, I saw a Youtube video where the hobbyist had the ULR checker and was happy with a test result of 0.03 ppm. Correct me if I'm wrong, but isn't 0.03 a desired result if you have the regular Phosphate checker?

https://www.hannainst.com/hubfs/006...ates-in-your-reef-tank--hanna-instruments.pdf

The Ultra low range checker is more accurate,
the HI713 LR range has a range ±0.04 ppm
the HI774 ULR has a range of +/- 0.02 ppm

Chasing a specific number will only cause problems, I would just recommend keeping phosphates between 0.01-0.10 until you get the hang of your tank and its nutrient consumption.
Many reefers have a preference on the high or low side but stability is more important than the specific number range.

 

[Koigula]

https://www.hannainst.com/hubfs/006...ates-in-your-reef-tank--hanna-instruments.pdf

The Ultra low range checker is more accurate,
the HI713 LR range has a range ±0.04 ppm
the HI774 ULR has a range of +/- 0.02 ppm

Chasing a specific number will only cause problems, I would just recommend keeping phosphates between 0.01-0.10 until you get the hang of your tank and its nutrient consumption.
Many reefers have a preference on the high or low side but stability is more important than the specific number range.

There is banter of the vendor specs all over being repeated on accuracy.

Run both together and then show results. Phosporous test will be 4-6 times higher if you convert to PO4 as ppm.

 

[fushi]

There is banter of the vendor specs all over being repeated on accuracy.

Run both together and then show results. Phosporous test will be 4-6 times higher if you convert to PO4 as ppm.

That sounds exactly inline with the manufactures specified range.

 

[fushi]

HI713 ±0.04 ppm ±4% of reading
HI774 ±0.02 ppm ±5% of reading (same as the HI736 but converts to ppm phosphate)

Lets keep it simple and use a PO4 level in the testing rang of both checkers of 0.05

So lets say the actual PO4 reading is 0.05
The HI713 checker could potentially read 0.09 (+0.04 ppm)
The HI774 checker could potentially read 0.03 (-0.02 ppm)

A bit of a difference
They also state a ±% difference which could make the difference in readings greater at different values.


So the moral of the story is testing is great but not perfect, and for best results we should use the ULR checker if we are going to use a hanna checker to make dosing decisions at ranges of 0.00 to 0.90 ppm.
Like most things it ain't perfect but it gets you close enough.
Also some people may not get the best results due to their lack of consistency in testing procedure.

Hope this helps.

 

[Randy Holmes-Farley Verified Community Expert]

There is banter of the vendor specs all over being repeated on accuracy.

Run both together and then show results. Phosporous test will be 4-6 times higher if you convert to PO4 as ppm.

I've not actually seen that result reported in a way that I recall it.

You are claiming that one or both is systematically incorrect in the same direction?

Which do you think is off and why do you think it the culprit?

 

[Koigula]

Let me follow up in a week with a data table to make discussion more useful. I need new tubes at this point and will show results.