What ph number to believe

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You are misinterpreting what was said and unfortunately I have not been able to explain to you why. I have tried to help you to understand that level of precision that you seek cannot be offered by the devices that you are using. It is really that simple.
Also if they claim it is accurate to plus or minus .1. That means they should have taken the temperature error into account as that goes into their ph reading.
 
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We are talking about what the manufacturer claims. That’s what he brought up, so that’s what we discussed.
And you saying I think the marketing gimmick is the Bible and am too pig headed to see the truth when I literally just told you with evidence that I don’t believe what the manufacturer claims is about the most confusing thing I have heard in a long while. Good job
 
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@Vinny@GHLUSA
There are claims being made on this post that GHL probes accuracy of .1 is actually only accurate to .2 because of rounding and temperature errors. This is serious because it would mean that my 2 probes could read 7.9 for one and 8.3 for the other and still be accurate. Spanning the entire acceptable ph range from low to high. Can you confirm or deny this claim?
 

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Several of us have attempted to help you to understand:
- the limitations of the equipment
- what +/- accuracy means
- a bit of insight into why the decimal point in the pH units is rounded from the actual value being read.
-how this related to different devices being so far apart on the same test solution

If you feel the device, marketing or accuracy claims are problematic then I suggest opening a support ticket with the manufacturer. I don't wish to argue with you, I am just trying give you insight into why you can't get the readings you are hoping to get.

I tied... I am done. Happy reefing.
 
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Several of us have attempted to help you to understand:
- the limitations of the equipment
- what +/- accuracy means
- a bit of insight into why the decimal point in the pH units is rounded from the actual value being read.
-how this related to different devices being so far apart on the same test solution

If you feel the device, marketing or accuracy claims are problematic then I suggest opening a support ticket with the manufacturer. I don't wish to argue with you, I am just trying give you insight into why you can't get the readings you are hoping to get.

I tied... I am done. Happy reefing.
Your claim is that a GHL probe is only accurate to .2. Meaning it could be accurate from 7.9 to 8.3. Making the probe completely useless. If you are right, there is no point to anybody using one of these probes.

Why would I open a ticket, we are talking about claimed accuracy. Good god nobody makes any sense today.
 

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Have never seen someone so confuse on accuracy... your have it backwards its not the accuracy of the probe at all.

in this case what you are terming accuracy = electrode slope and offset from the zero point of 7.

Im not a GHL user but i just looked up some info about thier probes - the electrode slope at 25 degree C > 95% of the theoretical value (of the slope) and zero offset < 20 mV

to measure accuracy you would need to know more about the device thats reading the probes output to determine accuracy. There is a guy on here named Lasse who knows all about GHL , suggest talking to him about the accuracy of thier ghl computer device....

If you dont understand electrode slope. (say you change to a different probe).. your accuracy is still going to be coming from the reader not the probe.
 
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Have never seen someone so confuse on accuracy... your have it backwards its not the accuracy of the probe at all.

in this case what you are terming accuracy = electrode slope and offset from the zero point of 7.

Im not a GHL user but i just looked up some info about thier probes - the electrode slope at 25 degree C > 95% of the theoretical value (of the slope) and zero offset < 20 mV

to measure accuracy you would need to know more about the device thats reading the probes output to determine accuracy. There is a guy on here named Lasse who knows all about GHL , suggest talking to him about the accuracy of thier ghl computer device....

to dumb it down a bit.....if you dont understand electrode slope. (say you change to a different probe).. your accuracy is still going to be coming from the reader not the probe.
So to clarify, because this is what is being discussed. You believe the GHL has a manufacturer error of +\-.2? Meaning it is within its limits read either 7.9 or 8.3. Because I think GHL would have a big problem with that. And we are arguing about what their limits are.
 
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Have never seen someone so confuse on accuracy... your have it backwards its not the accuracy of the probe at all.

in this case what you are terming accuracy = electrode slope and offset from the zero point of 7.

Im not a GHL user but i just looked up some info about thier probes - the electrode slope at 25 degree C > 95% of the theoretical value (of the slope) and zero offset < 20 mV

to measure accuracy you would need to know more about the device thats reading the probes output to determine accuracy. There is a guy on here named Lasse who knows all about GHL , suggest talking to him about the accuracy of thier ghl computer device....

to dumb it down a bit.....if you dont understand electrode slope. (say you change to a different probe).. your accuracy is still going to be coming from the reader not the probe.
Are you trying to sound smart? Because what we are talking about is super simple. And I’m not talking to you about being confused. Your last message was one of the most confusing things I have ever read.
 

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Your claim is that a GHL probe is only accurate to .2. Meaning it could be accurate from 7.9 to 8.3. Making the probe completely useless. If you are right, there is no point to anybody using one of these probes.

Why would I open a ticket, we are talking about claimed accuracy. Good god nobody makes any sense today.
I am telling you to open a support ticket and take it up with them. Several people here have tried to help you (including the moderator and resident expert of this forum) and are clearly not giving you the answer that you want to hear. As well, your posts are becoming increasingly combative which means meaningful conversation is over. Randy asked everyone to move on, as I assume he saw this coming from afar.
 
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You asking me to open a ticket is so confusing. We are arguing about what they claim! What is there to open a ticket about?

I love how somebody calls me pigheaded and I am combative because they are on your side.

And I will say it one last time. You claiming that GHL has a manufacturer acceptable range of +\-.2 meaning for example 7.9-8.3 is an acceptable reading for an actual ph of 8.0 is dead wrong and there is no way they would agree with you on their own claims. It is crazy to think they would be okay with such a massive error range. You can’t talk your way out of it, you’re wrong.
 

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The only accuracy that probe can guarantee is that if its dipped in ph 7.0 fluid it should read between 6.95 and 7.05 and if you dip it in ph 9 buffer it should read 8.95 to 9.05 and thats only at 25degrees C.

the accuracy you crave is not in the probe, its in the device reading the probes output. in your case its a ghl computer.
whatever accuracy it can provide would be something that ghl might or might not even know, its obviously accurate enough for the users of there product which sells worldwide. the results are reliable enough.
,

understand the probe you have is a basically a toy. the probes that reefkeepers use are not "accurate" in the sub $100 range when real ph probes are $4digits. I design methane injection systems for waste water treatment plants. My probes at work all have cases that cost as much as an apex or ghl computer lol.
 
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The only accuracy that probe can guarantee is that if its dipped in ph 7.0 fluid it should read between 6.95 and 7.05 and if you dip it in ph 9 buffer it should read 8.95 to 9.05 and thats only at 25degrees C.

the accuracy you crave is not in the probe, its in the device reading the probes output. in your case its a ghl computer.
whatever accuracy it can provide would be something that ghl might or might not even know, its obviously accurate enough for the users of there product which sells worldwide. the results are reliable enough.
,

understand the probe you have is a basically a toy. the probes that reefkeepers use are not "accurate" in the sub $100 range when real ph probes are $4digits. I design methane injection systems for waste water treatment plants. My probes at work all have cases that cost as much as an apex or ghl computer lol.
If it is only accurate to +\- .2(the entire usable range of reef ph ex7.9-8.3. Then it is not accurate enough for worldwide reef keeper sales.

yeah I’m getting a lot of I’m smart and assume you’re dumb from the people on this post. That attitude gives you little room to learn and in my experience, is bound to make you look like an idiot. And if you looked, you would see it in this conversation l.
 
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You asking me to open a ticket is so confusing. We are arguing about what they claim! What is there to open a ticket about?

I love how somebody calls me pigheaded and I am combative because they are on your side.

And I will say it one last time. You claiming that GHL has a manufacturer acceptable range of +\-.2 meaning for example 7.9-8.3 is an acceptable reading for an actual ph of 8.0 is dead wrong and there is no way they would agree with you on their own claims. It is crazy to think they would be okay with such a massive error range. You can’t talk your way out of it, you’re wrong.
That is not what I said and I am not on anybodies side. If you feel that the manufacturer's claims are incorrect or that your device does not meet those claims, then you need to consult with them. I can't help you further and do not wish to continue a fruitless and circular conversation with you.
 

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again you misuse the word accurate ... what are you saying is accurate to .2.. , whats accurate to +-.2 the ghl , the probe, ?? the only published numbers i see from ghl is what i gave you a few posts ago on their probes
"
i looked up the specs on your probe you you have there the electrode slope at 25 degree C > 95% of the theoretical value (of the slope) and zero offset < 20 m

the ghl or apex or hydos (they all use similiar grade probes) are all accurate enough for thousands of reefkeepers, you seem to be the special one.
 
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again you misuse the word accurate ... what are you saying is accurate to .2.. , whats accurate to +-.2 the ghl , the probe, ?? the only published numbers i see from ghl is what i gave you a few posts ago on their probes
"
i looked up the specs on your probe you you have there the electrode slope at 25 degree C > 95% of the theoretical value (of the slope) and zero offset < 20 m

the ghl or apex or hydos (they all use similiar grade probes) are all accurate enough for thousands of reefkeepers, you seem to be the special one.
it was established earlier the reading of GHL is accurate to .1. From a screenshot from GHL. BeanAnimal believes that with rounding and temperature probe inaccuracies that the reading is only good to .2. Which again, gives such a huge range that is is literally not usable.
 
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Discussing the accuracy of just the probe or just the computer is really useless. The reading, accuracy of the reading. If I ever said accuracy of the probe I was talking about the actual reading given from the probe. Thought that would a given but maybe not.
 
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again you misuse the word accurate ... what are you saying is accurate to .2.. , whats accurate to +-.2 the ghl , the probe, ?? the only published numbers i see from ghl is what i gave you a few posts ago on their probes
"
i looked up the specs on your probe you you have there the electrode slope at 25 degree C > 95% of the theoretical value (of the slope) and zero offset < 20 m

the ghl or apex or hydos (they all use similiar grade probes) are all accurate enough for thousands of reefkeepers, you seem to be the special one.
So a range of 7.9 to 8.3 for an actual ph of 8.0 is acceptable for everyone but me? Ha! Either that is not correct, which is what I am saying. Or nobody has any clue how important ph is to stony coral growth.
 
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If you keep stony coral and you think there is no difference between knowing your ph is 7.9 or 8.3, you have a lot to learn.
 

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this is the basic specs of a low end lab grade mettler toledo s400 "specs" this is a benchtop unit.. by lab standards its about as cheap as you can get and still have a "real " piece of ph reading equipment for the work we do at our faciliy.
this is something you would find in a decent college chemistry lab.

notice how they use MV range, resolution and with the right probe it can read out to 3 decimal places. and its quite accurate... none of this "accuracy " is listed for any of the apex, ghl , hydros that i can find easily online.

see the difference ...


Temperature accuracy
pH-range-2.000 to 20.000
pH-resolutionSelectable 0.1, 0.01, 0.001
pH-relative accuracy±0.002
mV-range-2000 to 2000
mV-resolutionselectable 0.1/1
mV-relative accuracy±0.1
Temperature Range-30.0 to 130.0 °C
Temperature resolution0.1°C
 

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