infinite0180
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I think your confusing the 774 which is a brand new version that is ULR with the 713...
Which hanna phosphate checker?
I think your confusing the 774 which is a brand new version that is ULR with the 713...
Welcome to R2R! ;Bookworm I assume you meant to say you had the previous model (713), as the 774 is newly released, but I understood what you meant. Glad you found the conversion chart helpful!
It isn't bad. It works just as well as the others with the exception of the range and precision ( ±0.04 ppm). I accidentally bought this one and while the precision isn't there it gives a consistent reading every time. I use the value / reading as a guide and can easily see trends when looking at the results on paper or via the logs in Apex.
I'm all for buying the correct one first - save yourself 50 bucks. I'm just not giving them another 50 when the 713 works perfectly fine for me
If you’re not in the camp of folks that insists on keeping their phosphates below .03 I don’t see a reason to switch either. Whatever works for you. But I agree, for those buying their first one, it’s best to go with one of the ULR models.
Honestly, like I said, you can’t go wrong either way. And I’m confident they’re both equally reliable. Hanna is a reputable company and the technology is the same, it’s just a colorimeter with different programming. With that said, I believe my difference in margin of error calculations is correct but I’m still curious about the suggestion that was made earlier that they have the same margin of error.
@wesman42 do you mind please elaborating on your comment for us? If you have additional information that would be useful it’d be much appreciated.
Update:
I just spoke with Kevin, @Hanna Instruments Marine products head, and he confirmed what I had previously stated. There are a couple of additional changes with the 774, such as the ppb to ppm conversion, the longer timer before time out, and an increased detection window for the solutions (although he said it’s still advised to follow the 2 minutes of shaking and 3 minutes of letting it sit before developing a reading). He also confirmed that for those keeping an ultra-low nutrient system, the 736 is .005 ppm more accurate and that is why the 736 model is not being phased out.
He said he would chime in on this thread in a couple days as well to clear up anything that might need clarification. Hope this is helpful to @infinite0180 and anyone else who is trying to make the decision.
I just spoke with Kevin, @Hanna Instruments Marine products head, and he confirmed what I had previously stated. There are a couple of additional changes with the 774, such as the ppb to ppm conversion, the longer timer before time out, and an increased detection window for the solutions (although he said it’s still advised to follow the 2 minutes of shaking and 3 minutes of letting it sit before developing a reading). He also confirmed that for those keeping an ultra-low nutrient system, the 736 is .005 ppm more accurate and that is why the 736 model is not being phased out.
He said he would chime in on this thread in a couple days as well to clear up anything that might need clarification. Hope this is helpful to @infinite0180 and anyone else who is trying to make the decision.
infinite0180
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Update:
I just spoke with Kevin, @Hanna Instruments Marine products head, and he confirmed what I had previously stated. There are a couple of additional changes with the 774, such as the ppb to ppm conversion, the longer timer before time out, and an increased detection window for the solutions (although he said it’s still advised to follow the 2 minutes of shaking and 3 minutes of letting it sit before developing a reading). He also confirmed that for those keeping an ultra-low nutrient system, the 736 is .005 ppm more accurate and that is why the 736 model is not being phased out.
He said he would chime in on this thread in a couple days as well to clear up anything that might need clarification. Hope this is helpful to @infinite0180 and anyone else who is trying to make the decision.
Hahah awesome! Thanks for helping out!
If you’re not in the camp of folks that insists on keeping their phosphates below .03 I don’t see a reason to switch either. Whatever works for you. But I agree, for those buying their first one, it’s best to go with one of the ULR models.
Well now, I'm gonna have to kinda disagree here...a few months back I decided to transition from fish only to mixed reef, so it was time to pay better attention to my parameters. It sounded like ULR was the way to go, so I purchased a 736. That's when I found out that the range of the 736 was much too small for my existing high phosphate levels, so all the meter displayed was a blinking upper limit. So I went out and bought a 713 so that I could actually measure what I have and monitor the phosphate levels as I hopefully reduce them. So I guess the moral of my story is, if you are going to be buying your first Hanna phosphate meter, make sure you get one that can actually measure your phosphate level!
Well now, I'm gonna have to kinda disagree here...a few months back I decided to transition from fish only to mixed reef, so it was time to pay better attention to my parameters. It sounded like ULR was the way to go, so I purchased a 736. That's when I found out that the range of the 736 was much too small for my existing high phosphate levels, so all the meter displayed was a blinking upper limit. So I went out and bought a 713 so that I could actually measure what I have and monitor the phosphate levels as I hopefully reduce them. So I guess the moral of my story is, if you are going to be buying your first Hanna phosphate meter, make sure you get one that can actually measure your phosphate level!
Thank you for adding this. That’s a good point. I just figured if you’re over the phosphate level that the ULR checkers are capable of testing, that’s so extremely high that regardless of what it is, you should be getting down to the bottom of it and reducing them until it’s reading on the ULR checkers because the high range of the ULR checkers is still very high. That being said, it’s still good to know where you’re at and bring them down accordingly so depending on your situation you may find the 713 to be more useful initially.
Thank you for adding this. That’s a good point. I just figured if you’re over the phosphate level that the ULR checkers are capable of testing, that’s so extremely high that regardless of what it is, you should be getting down to the bottom of it and reducing them until it’s reading on the ULR checkers because the high range of the ULR checkers is still very high. That being said, it’s still good to know where you’re at and bring them down accordingly so depending on your situation you may find the 713 to be more useful initially.
Being able to someday use my 736 is on my bucket list
.
Being able to someday use my 736 is on my bucket list
Haha you’ll get there!!
ShanesClowns
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Was going to buy the 736 until I went on you tube and watched the ease of use and accuracy of the 774 , it also has the longer on time , which was issues with the older models , I have the 774 and it is great , and very accurate and super easy to use.
There is a reason why they came out with the new one and it works great, no conversion just results.
My 2 cents good luck
Wish they would come out with a PH , magnesium and nitrate checker , tired of looking at colors.
There is a reason why they came out with the new one and it works great, no conversion just results.
My 2 cents good luck
Wish they would come out with a PH , magnesium and nitrate checker , tired of looking at colors.
I use the HI-736, and log it into APEX Fusion, which does the conversion to ppm automatically
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w2inc
Active Member
It did get me thinking and allowed me to waste a good part of my day doing math, but in the end, I just don't know what "+-.o2 ppm +-5%" means. Are we looking at a 20 point scale and by adding .02 we will compensate the ratio by subtracting 5%? Is it +-.02 ppm (the reading) and then +-5% of that result?.Is it? I used these accuracy +/- postings off Hanna’s website and the conversion chart I’ve posted above.
HI-736:
HI-774:
Using the posted accuracy numbers from Hanna and the above conversion chart, the HI-774 has a margin of error of .02 ppm, while the margin of error of +/-5 ppb with the HI-736 is between .014-.016 ppm (assuming the conversion chart is accurate).
Am I missing something here?
It cant be either or except in one situation. The +-.02 or +-5% is only correct if you have a reading of .4 (since 5% of .4 is .02).
If +- 5% is always true then, +-.02 ppm is not always true. Or the opposite if +-.02 is true, then +-5% can not always be true.
If your reading was .06, and you use +-5% is +-.003. You can have .057 ppm or .o63 ppm, but you don't get to have+-2 which is .08 ppm and .04 ppm at the same time.
Does anyone know things? I have a Bachelors in Fine Arts. Math has always been weak spot for me. I was feeling pretty smart running figures this morning until I realized that I didn't understand the equation.
I briefly discussed the +/-5% (which I believe is added to the first posted +/-) with Kevin but I prefer to let him explain it when he chimes in to make sure we get accurate info regarding that. He did mention that it was almost negligible but I’ll let him break it down.
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w2inc
Active Member
I don't know how I overlooked that post from @infinite0180? Thanks for calling him Kevin! I would have got so much more done today if I had read it! I am still surprised that I decided to call BRS and ask them the difference rather than calling Hanna.Update:
I just spoke with Kevin, @Hanna Instruments Marine products head, and he confirmed what I had previously stated. There are a couple of additional changes with the 774, such as the ppb to ppm conversion, the longer timer before time out, and an increased detection window for the solutions (although he said it’s still advised to follow the 2 minutes of shaking and 3 minutes of letting it sit before developing a reading). He also confirmed that for those keeping an ultra-low nutrient system, the 736 is .005 ppm more accurate and that is why the 736 model is not being phased out.
He said he would chime in on this thread in a couple days as well to clear up anything that might need clarification. Hope this is helpful to @infinite0180 and anyone else who is trying to make the decision.
As far as the +-5%, I just got off the phone with a chemist that knew things. He said to:
Get the reading. Multiply by .05. Add that value to your +-.02 correction number and now you have the new adjusted correction number. Then +- the new adjusted correction number to the original reading. This gives your adjusted high and low possibilities.
I am excited to get the details from the rep. My chemist friend couldn't figure out how they could use the same 535nm light on both devices. It would be great to find out how the two solutions differ so I can let him know.
bluprntguy
Well-Known Member
The 736 is not that difficult to adjust to. Most people are shooting for 10 ppb (0.03 ppm) and want no higher than 30 ppb (approx 0.1 ppm). Those numbers become second nature after just a few uses.
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w2inc
Active Member
Thanks for chiming in. I really appreciate all the people who have taken time to share their experience. I agree that working in different units is just not that big of a deal. I would probably be happy with either one.
If you had to buy a new one today and it turns out that after accounting for the phosphorus to phosphate conversion they are both equally accurate. Would you want the new one that reads in common units and could have some kind of improvements on it?
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