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Which Hanna Phosphate Checker?


AquaKey

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If you're serious about your PO4 readings, then you should decide between the original Hanna HI736 ULR Phosphorus, or the newer Hanna HI774 ULR Phosphate.  There are some slight differences between these two models.  The HI736 measures Phosphorus, and you need to use a conversion chart to figure out what the actual Phosphate reading is.  But the original HI736 is more precise and has a more narrow range than the HI774 which directly reports the Phosphate reading without any conversion, while the HI774 has a higher range and is slightly less accurate.

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  • 2 weeks later...
38 minutes ago, MasterChief said:

The 774 is the same as the 736. The 774 does the conversion for you and displays in PPM.  The accuracies of both meters are the same +-5ppb vs 0.02ppm (considering meter resolution...)

the light sources are the same

testing methods are the same

hell even the reagent works in both

 

They are not the same.  The resolution of the 736 is nearly 3x better than the 774:

HI736 = 0.0036066 ppm Phosphate
HI774 = 0.0100000 ppm Phosphate

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52 minutes ago, MasterChief said:

This 👆🏻👆🏻  The 774 and 736 are pretty much the same, the 774 does the conversion for you. 

So you're simply going to ignore the fact that the resolution is nearly 3 times different as I posted above?

2 hours ago, SuncrestReef said:

They are not the same.  The resolution of the 736 is nearly 3x better than the 774:

HI736 = 0.0036066 ppm Phosphate
HI774 = 0.0100000 ppm Phosphate

 

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I was surprised at how heated this topic got and originally didn't want to add to it. But I couldn't understand why Hanna would update the 736 to the 774 and lose so much accuracy. I looked at SuncrestReef's details in his initial post and came to a different conclusion. 

Range: 736 is .00 to .6132 ppm phosphate;   744 is .00 to .9 ppm phosphate

Accuracy: 736 is .01533 ppm phosphate;   744 is .02 ppm phosphate

Reading resolution: 736 is .003066 ppm phosphate;   744 is .01 ppm phosphate

Conclusion: the 736 is more accurate, by just over 30%;   the 744 has a wider range, extending the range from .6132 to .9, both of which are greater than needed.; the resolution, or size of each digit that displays on the meter doesn't matter as it is smaller than the accuracy of the digit displayed;   the 736 requires conversion of the number displayed to get ppm phosphate.

I chose the 744 because it is easier to use and sufficiently accurate for me. I can see why others would prefer the 736.

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