It's a good thing to have back up ph tester

[ribbitt]

I have a bubba auto that is almost three months old leaves started to yellow tried adjusting my nutes because ph pen was reading right I thought. I was wrong I tested with my ph drops pen was way off plant is growing again leaves have greened up a bit .good idea to have a back up plant was doing awesome. Now won't get as much yield as I could of

[oldjarhead100]

it happens to use all ,then we get a good one to calibrate and I also have strips, when I get a crazy reading from my meter I put it right in 7.0 solution and calibrate it right away

[Aloner]

Calibration fluid is reasonably cheap on Amazon, as long as you're not checking your pen every other day.

[ribbitt]

All I had was the drops matched the 6.0 color and calibrated it to that seems to be close I use drops once a day now

[Potted]

I found a ph pen I like and trust it’s cheep so I always keep a extra on hand and strips as well.🙃

[DoctorJohnson]

All I had was the drops matched the 6.0 color and calibrated it to that seems to be close I use drops once a day now

So you calibrated your pH pen using drops? That's not gonna work. Just get a bottle of pH 7.0 calibration fluid, a must-have. You can buy the General Hydroponics brand at Amazon.