DIY Need info on re-calibrating pH Meter

[Buds Buddy]

Hey there Weed Guru's,
I'm not so sure my pH Pen is correct & would like to re-calibrate it. I have 2 solution packets (pH 4.01 & pH 6.86), but it says to use de-ionized water. Looked up de-ionized water but it looks quite expensive ($10 for a 16 oz. bottle). Is there a way to make de-ionized water yourself ? Is there another way to do this ? It would be cheaper to just buy a new pen at $10 a bottle of water. It also says to do the calibration @ 25 degrees celcius. No idea what that converts to in U.S. degrees but I can look that up.
Hope someone will shed some insight on re-calibrating a pH pen. Never done it before so it's a learning experience for me.
Thank you for any comments on this subject !

 

[Simplicio]

Hey there Weed Guru's,
I'm not so sure my pH Pen is correct & would like to re-calibrate it. I have 2 solution packets (pH 4.01 & pH 6.86), but it says to use de-ionized water. Looked up de-ionized water but it looks quite expensive ($10 for a 16 oz. bottle). Is there a way to make de-ionized water yourself ? Is there another way to do this ? It would be cheaper to just buy a new pen at $10 a bottle of water. It also says to do the calibration @ 25 degrees celcius. No idea what that converts to in U.S. degrees but I can look that up.
Hope someone will shed some insight on re-calibrating a pH pen. Never done it before so it's a learning experience for me.
Thank you for any comments on this subject !

Those packets contain a material, that when dissolved in water, gives a known pH.
Some pH pens can be (less accurately) calibrated using a single solution, the 6.86
You'll need a measuring device that can get you a known amount of liquid to mix up the solution.
Some pens automatically calibrate when you put them into the 6.86 solution, others require turning a tiny screw in the pen with a tiny screwdriver.
A jug of distilled water from the grocery store will probably work to mix the solution, but you can also buy already-made stuff online.

In any case, pH is very important, and can cause lockout deficiencies, so you need a way to verify the pH pen reading every now and then.
pH drops and strips work well, or just get a second cheap pen.

 

[Arthur]

Is it one of the yellow cheapies? I've always used distilled water for calibration.

 

[Buds Buddy]

Yes it's a yellow cheapie & it does have the little screwdriver. I also have a couple small bottles of the liquid drops for checking the pH. I forgot I had those till you mentioned it. I guess I can check to see if the pen is accurate against the test drops. I have 2 of the cheap pens so maybe one is correct. Glad you mentioned the drops. Thanks you guys. I'll pick up some distilled water if it's not & give that a shot before buying another pen. I usually pH to 6.4 every time so I'd like to keep things the same if possible.

 

[Arthur]

Was thinking back over that post and wanted to clarify.
I use distilled water to mix the pH packets. I use 2 small Tupperware containers and when done keep on the shelf for future reference. If something feels off, I can open and verify the probe without having to mix again.

 

[Simplicio]

Yes it's a yellow cheapie & it does have the little screwdriver. I also have a couple small bottles of the liquid drops for checking the pH. I forgot I had those till you mentioned it. I guess I can check to see if the pen is accurate against the test drops. I have 2 of the cheap pens so maybe one is correct. Glad you mentioned the drops. Thanks you guys. I'll pick up some distilled water if it's not & give that a shot before buying another pen. I usually pH to 6.4 every time so I'd like to keep things the same if possible.

Check the pH of the distilled water with both pens.
If the water's pure, the pH will be 7.0, so you might be able to tell which is the better pen.
I often use 2 pH pens, and average their readings.

 

[shumway]

Check the pH of the distilled water with both pens.
If the water's pure, the pH will be 7.0, so you might be able to tell which is the better pen.
I often use 2 pH pens, and average their readings.

Distilled is no good for checking ph,Not enough ions in the water to allow the prob to read properly and distilled will also loose that neutral ph once the bottle has been opened and CO2 starts dissolving into the water

 

[Simplicio]

Distilled is no good for checking ph,Not enough ions in the water to allow the prob to read properly and distilled will also loose that neutral ph once the bottle has been opened and CO2 starts dissolving into the water

pH is defined as the negative logarithm of the Hydrogen ion concentration, so a pH of 7 means plenty of hydrogen ions.
Pure water is probably the best medium to check a pH pen against, assuming it's pure water.
Air dissolved in pure H2O will change pH slightly, but that is easily avoided by keeping the distilled water lid on, so that the disslolution of air is negligible.
Even airstones have trouble dissolving air in water.

 

[Buds Buddy]

I use to use purified drinking water on my plants. Every time I checked the pH it was exactly 7.0 before adding pH down. Would that work ?