They are easy to calibrate.It usually involves putting the ph pen in a calibration solution which will be 7.You read the pen and if its high or lower then 7 there is a little screw on the pen you turn it and it adjust the ph reading. Once its at 7 take it out of the solution and its calibrated.Store the tip in storage solution or it will go bad and the calibration will be off again.The liquid ph isnt really cost effective figuring you have to ph your water daily for a few months and a ph pen is only like $24 and lasts forever basically
yes, but you also have batteries nad calibration solution, i just personal like the dropplets, simple and you follow the directions and you cant fuck up.... growing weed cost money buts it cheaper that buying it.
But batteries come with most meters and so does claibration and storage solution but even if theye didnt. Batteries cost 2 bucks will run for more then a year or 2 and the 2 solutions only cost maybe 12 bucks together which is enough for 5 or more years.So 14 bucks for 5 years is still cheaper then a little droplet kit and last way longer...oh and the digital pen is about 500 times more accurate then paper and drops