Accurate PH?

[jaysta]

I recently purchased one of those digital PH pens so I could start doing my water properly. I used the calibrate solutions that came with it and thoguht I had calibrated as per instructions and at room temperatures.

What would cause my calibration to go out of whack? Over the last few days I couldn't work out why my plants are all turning yellow, and it suddenly dawned on me that this only started happening when I started to PH my water!

Obviously the PH must be out? I don get why when I have calibrated using a 4 and 7 solution, why would my readings be to the point of turning my plants yellow

I've pissed the PH pen off and gone back to just watering how I normally did without adjusting PH until I can work out why my readings are so far out.

Are there better ways then having to calibrate/rely on this Digital pen, are the strips better in terms of not having to calibrate them?

 

[AutoWonders]

To double check, which digital pen did you buy and are you sure that it can be calibrated? Did you use 7 solution, then 4? I am currently using the Apera PH60 and it has worked very well. I've owned a bunch of ph pens (expensive as well) over the years and all have at some point, staring drifting pretty badly. The PH60 is hanging tough.

 

[jaysta]

Some $20 pen off eBay? They all look similar, comes with the calibrate powders 7/4, yes, I had to calibrate to the powders with a screw driver, I don't trust the bloody thing now :/

Might check out the apera

 

[St. Tom]

Some $20 pen off eBay? They all look similar, comes with the calibrate powders 7/4, yes, I had to calibrate to the powders with a screw driver, I don't trust the bloody thing now :/

Might check out the apera

The ones with the screw in the back are ok in a jam also with them I've only ever used the 7.0 calibration fluid also I have an essential ph meter it's a cracker also bluelab make some great ph and ec meters