2 Ph Pens, 2 Readings Why?

[vangs]

i got a bluelab ph pen and bluelab guardian. when i use them on a 50gal ro water both pen and guardian read 7.1 but when i use the pen and guardian on my other 50 gal ro water that ive put PH, the bluelab guardian reads 6.4 and the pen reads 6.0 does anyone know why this is happening?

 

[DrMcSkunkins]

The 7.1 is what they read when the ph is out of range, if you calibrate them both the should read the same. Always use the ph calibration powder closest to the ph range that you will be measuring. i.e. use 6.8 ph powder if you grow in dirt or 5.8 ph powder if you grow in coco/hydro.

 

[iKharon]

Some require you to set it in tap water for 30 min to an hour to adjust... sounds like poor calibration to me. Unless one is just an el cheapo

 

[HydroGuy]

Definitely recalibrate but on a side note it is hard for ph meters to get an accurate read in pure ro water. I would still recalibrate.

 

[iKharon]

Mines perfect 6.3 :)

 

[Natural]

bluelab sucks imho
When probes are new..they need to be soaked in tap water for 24 hrs, before your first calibration. Always, calibrate your meters with at least 7 and 4. Store probe end in tap water when not in use.
Bench top meters always seem more accurate to me.
Been using Milwaukee and I like them alot.

 

[vangs]

i calibrated them both, seems to be fine.... thanks guys