pH buffer, what's the difference becide price ?

[Holst]

Hi everyone.
I have some pH4 and pH7 buffer solution for calibrating my pH probe, but is there any difference in the various products becide price ? They are all 4.01 at 25°C and 7.00 at 25°C..
I can see that I can buy it alot cheeper from Agro-culture shops than from the Aquarium shops..
Is it just the same but different price or is there anything to be aware of ?

 

[blaxsun]

Good question. How much of a price difference are we talking about?

 

[mdb_talon]

Just guessing here but I always just go with the cheapest option and assume they are all going to be adequate. I use 7 and 10 (rather than 4) to calibrate though.

 

[Malcontent]

I did a cursory price analysis for my own curiosity a few months ago. The cheapest are no-name powder packets on Amazon.

The dry stuff (powder/tablets) appear to have the longest shelf life and are among the most economical.

I use the Lovibond tablets in 100 quantities.

I have no idea how good the generic Amazon stuff is just that it's very cheap. It might be a bit of a false economy though since 250 mL is more than you typically need and you can't really save the stuff after you reconstitute it with RO/DI water.

 

[SPS2020]

I believe you mean pH Calibration Solution, not Buffer. Also, if it is for saltwater, you would want ph7 and pH10 Calibration Solutions.

 

[Malcontent]

I believe you mean pH Calibration Solution, not Buffer. Also, if it is for saltwater, you would want ph7 and pH10 Calibration Solutions.

They call them pH buffers for some strange reason.

 

[SPS2020]

They call them pH buffers for some strange reason.

Ah...duly noted!

 

[Holst]

Just guessing here but I always just go with the cheapest option and assume they are all going to be adequate. I use 7 and 10 (rather than 4) to calibrate though.

But why not use 4 and 10 then to get the biggest range and therefore the most accurate reading ?

 

[mdb_talon]

But why not use 4 and 10 then to get the biggest range and therefore the most accurate reading ?

Because you dont care about PH values near 4. The most accurate readings that you care about (around 8) are going to be by calibrating with solutions near that value. This is why in reefing the standard is to calibrate using 7 and 10.

 

[Holst]

Because you dont care about PH values near 4. The most accurate readings that you care about (around 8) are going to be by calibrating with solutions near that value. This is why in reefing the standard is to calibrate using 7 and 10.

Okay..
But when calibrating all sorts of process instruments you want to calibrate it across the widest range as possible to get the most precise reading.. That would in my head be from 4 to 10 and not from 7 to 10.
But I think I will buy some 10pH solution for this calibration. And the question was actually if there is any difference in the cheepest and the most expensive solution..
But thank you for your input mate I will read a bit more about calibrating this pH meter that I got.

 

[mdb_talon]

Okay..
But when calibrating all sorts of process instruments you want to calibrate it across the widest range as possible to get the most precise reading.. That would in my head be from 4 to 10 and not from 7 to 10.
But I think I will buy some 10pH solution for this calibration. And the question was actually if there is any difference in the cheepest and the most expensive solution..
But thank you for your input mate I will read a bit more about calibrating this pH meter that I got.

This article below gives an analysis of various ph solutions and accuracy and the impact of one of the solutions being off(and also touches on why it is better to use 7 and 10 if you are monitoring tank ph versus using 4)

http://reefkeeping.com/issues/2005-02/rhf/index.php

 

[Holst]

This article below gives an analysis of various ph solutions and accuracy and the impact of one of the solutions being off(and also touches on why it is better to use 7 and 10 if you are monitoring tank ph versus using 4)

http://reefkeeping.com/issues/2005-02/rhf/index.php

Cool, thanks mate !