Hannah Phosphate checked or ULR phosphate ???

[ivanzlemus]

What is the difference between a regular Hannah phosphate checker and the ultra low version ? Just getting into dosing and I am confused on wich one to use

 

[exnisstech]

ULR is the most common and what I use. I don't know the specs of the regular PO4 but the ULR maxes out at 0.9

 

[Tangdora]

Ulr has 0.02 better accuracy in individual result readings . That’s about it. It trying to stay below .1 and about 0 is your goal ULR is better. Above that probably makes no difference in which you use. Also have the ULR as I have no intent of running phos about .9 so I’ll take the slight more accurate meter

 

[EnterName]

HI-717: 0.0 to 30.0ppm in 0.1ppm steps.

HI-774 (ULR): 0.00 to 0.90 in 0.01ppm steps.

HI-736 (ULR): 0 to 200 ppb. Measures in "Phosphorus" (P) not "Phosphate" (PO4). Values have to be converted by multiplying with 0.003066 if you want Phosphate readings in ppm which are more commonly used in the hobby.

Note: The actual precision/error is larger than the step size, so measurements won't be exact down to the last digit.

 

[mcarroll]

What is the difference between a regular Hannah phosphate checker and the ultra low version ? Just getting into dosing and I am confused on wich one to use

Most folks get the ULTRA version because "reefs should have no nutrients".

Unfortunately that's hooey.

The regular unit covers a much more useful range, and won't tempt you to lower nutrients toward "zero" and wreck your tank.

 

[exnisstech]

Most folks get the ULTRA version because "reefs should have no nutrients".

Unfortunately that's hooey.

The regular unit covers a much more useful range, and won't tempt you to lower nutrients toward "zero" and wreck your tank.

I wish I would have gone with the regular unit. My curiosity has me wondering how high my tank really is because quite often I get a flashing 0.9 . Most people don't run it that high so the ULR works for the majority.

 

[mcarroll]

You can dilute your sample with 50% clean saltwater and then double the result the tester generates, but it also compounds the uncertainty of the unit as well, so half as accurate/precise too I guess. Usually worth it to get a real number tho.

 

[BriDroid]

I use the phosphorus ULR only because I bought it used on FB marketplace. It works great for me, but I keep my PO4 0.04-0.06ppm.

 

[EnterName]

I would use the ULR meter. I have the HI-736 but would recommend the HI-774 for ease of use.

Coral reefs have something between 0.003 ppm and 0.036 ppm PO₄ iirc. So you can still go 25 times higher than a phosphate-rich coral reef and 300 times higher than a low-phosphate reef until you max out the meter. It's far more accurate within the range most people run their tanks and the better option if you like to stay within Randy's recommended target range for phosphate of 0.06 ppm to 0.3 ppm PO₄.

Nutrients are certainly essential, but high phosphate levels may also have some negative effects (Koop et al., 2001 & Nalley et al., 2023), so I personally don't see a reason why you would want to go above 0.90ppm PO₄. Regardless of whether you want ultra-low or very high phosphate, you can achieve both within this checker's range.

You also have to remember that not all organisms even have to rely on the dissolved phosphate you can detect. Corals can digest particulate matter, and there are also ways for some organisms to get the phosphate bound to calcium carbonate (Millero et al., 2001), so having low readings is not the same as an actual phosphate limitation, especially considering that coral reefs can deal with levels below the meter's detection limit.