calibrating a ph meter

[eaze333]

Hi,
I am trying to make sense of the instructions that came with on of those ph meters i bought off ebay from china. It comes with 2 pack of powdered solution to calibrate. I just have no idea with how much water you are supposed to mix the packets. It is a PH-009(I) pen type ph meter. on the back of the packets of 4.00 and 6.86 solution there are different measures like 0.05m,0.025m. I got no clue.
If anyone can help it would be fantastic.
Thanks
Eric

 

[steved13]

First, are you sure your pH meter will measure in the range you need?

If it will you need to buy some different cal fluids, usually 7.0 and 10.0 or near there (7.01 10.01). The cal packets you have would be for the acidic range, you need a pH meter that will measure in the basic or alkaline range and calibrate in that range.

 

[eaze333]

The instructions state that it measures from 0 to 14. I just don't know what to do with the packets. I guess I'll buy some cal fluid at a the LFS I hope.

 

[steved13]

Calibration that far from where you want to measure wouldn't be very accurate, even if you knew how to mix the packets.

 

[Reefmack]

Are the packets powder or liquid? If it's liquid just cut off the top of a packet and use that. Putting the open liquid packet in a small cup may help (not pouring it in - just to hold the packet so it doesn't spill). If it's a powder go back to the Ebay seller and ask how much water to add to the packet contents.

steved13 is correct - having a pH 10 standard is good. A lot of pH meters come with 4,7,10 calibration standards. Using the 4 & 6.86 supplied may get you started till you can get other calibration standards.