pH pen is 6.86, but can't find pH 6.86 solution

[JSB99]

I found my 4.01, 6.86, and 9.18 packets, and calibrated my pen. So far it's working well. But it's a cheapo, so I do plan on getting an Apera soon.

I was thinking that these packets were single-use only. I didn't think to store the buffers in containers (I used air-tight Ball jars).

After looking around at other pens, I think I figured something out. The auto-calibrating pens with ATC, which is what I have, all use these three buffers for calibration. But with the manual calibration pens, pH7.0 and pH4.0 seem to be the most common buffers. In fact, my local hydro store only carries these two.

 

[Gquebed]

News flash... pH pens at even $100 a pop arent accurate enough to meausre to 100ths. They have an accuracy range of -/+ of 2%, which isnt great. When measuring in 10ths even...

So calibrate to 7 and call it day... and hope it gets ya close enough. In fact, the same can be said of pH pen $100 or under...

 

[Xs121]

Amen to above post

 

[Canadain Closet Gardener]

I have 3 yellow cheap Chinese pens that I use. I can generally tell if they need calibrating when they start giving different readings. I think I paid less than $25 for all three.
Cheers
CCG

 

[JSB99]

News flash... pH pens at even $100 a pop arent accurate enough to meausre to 100ths. They have an accuracy range of -/+ of 2%, which isnt great. When measuring in 10ths even...

So calibrate to 7 and call it day... and hope it gets ya close enough. In fact, the same can be said of pH pen $100 or under...

I have 3 yellow cheap Chinese pens that I use. I can generally tell if they need calibrating when they start giving different readings. I think I paid less than $25 for all three.
Cheers
CCG

I use my pH kit to verify levels all the time.

 

[gwheels]

Get a bluelab. They work and are waterproof and easy to calibrate . I had a cheap ph pen and TDS meter. The TDS meter was not waterproof so that didnt last long (I fill 5 gallon water bottles with solution and kerplunk).
Now that i have good waterproof meters I can honestly say they are worth every penny.

 

[Hollatchaboy]

I have a bluelab guardian ph/temp/ec meter. I also have the vivosun ph and tds meters. The cheap yellow vivosun meter works just as well as the bluelab ph probe imo.i rarely calibrate either. They both work great.

 

[Kalebaiden]

All pH pens have a little screw to calibrate the pen.

If your pen calibrates to 6.8whatever and you have a solution you know is 7.0, turn the screw until the pen tests the solution and reads 7.0.

No big deal.

 

[xtsho]

All pH pens have a little screw to calibrate the pen.

If your pen calibrates to 6.8whatever and you have a solution you know is 7.0, turn the screw until the pen tests the solution and reads 7.0.

No big deal.

The BlueLab I have doesn't have a screw. It's auto-calibrating. You just put it in the calibration solution and press the calibrate button. I just took off the top where the battery goes to double check and no screw. All the other pens I've had in the past did have a screw though.

 

[Hollatchaboy]

My bluelab is a meter, not a pen, so it doesn't have a adjustment screw. I'm not sure if my vivosun does but I'll check when I get home in a few days

 

[piratebug]

Where are you located? Just get some type of liquid that has that pH level, like Dollar Tree's, Family Dollar, or Dollar General's, Crystal Geyser Spring Water 6.87, etc etc... nestle pure life water is also pH 6.87

 

[Hollatchaboy]

Thanks...I didn't know that. Might come in handy for my vivosun ph pen.