Cleaning hydro gear

Hi People. My hanna ph pen started giving me readings of 0.2 ph in water that has been through an R.O. filter. I looked closer and it looked like it had a build up of nutrients on the paper strip. Does anyone have some good tips for cleaning in general? Thanks!

Sounds like you need to do several things and I'm not sure what you mean by "build up on paper strip"?

#1 clean the sensor. Very, very gently with a Q-TIP and just water. Soak pen in storage solution for an hour or so before using the QTip.
#2 calibrate your meter. Really important to do this at least once a month. Check your Hanna pen's manual on how to do this.
#3 after every use, dip meter in clean water. Tap water is just fine.
#4 start using a pH meter storage solution whenever you are done using the meter

Cheers,
SB

^^^^^ what they said. I also have a cleaning solution.