i just bought my self a PH pen for when i do my next hydro grow.
its only a cheapo thing from hong kong less than 20 quid of fleabay.
i've had a little fiddle about with it & pretty sure its out of calibration as i know my tap water is 6.8 to 7 (i also did a test with the liquid ph tester kit) & i'm getting a reading over 8 with this PH pen.
i've read the instructions on how to calibrate it but still not quite sure how to do it.
i'll type exactley what the instructions say ;

1.immerse the electrode in ph 6.86(under the tempreture of 25c)standard buffer solution of phosphate,& gently shake the electrod.

2.regulate the trimmer with a screw driver until the buffer solution value corresponding to the measurement temperature is obtained.

3.immerse the electrode in ph401 or ph918 the standard buffer solution of borax.

4.after about one minute,untill the buffer soluion value coresponding to the measurement temperture is obtained.



i have 2 bottle of solution 1 is ph4.003 & the other is ph6.864.

can any 1 shed any better light on how i'm suppose to calibrate this thing.

cheers

pour some of the calibration fluid into an egg cup or something and put the ph meter in it
take the reading
if you put it in the 6.86 solution and it dosent read that then adjust the small screw on it(usually on the back ) until it reaches 6.86ish

then wash it off and put it in the 4.0 solution and then adjust the screw to that

its quite a small screw and usually needs a precision screwdriver to get at it.usually get one with the meter

yes i did get a screwdriver with it & will try that now,why did'nt there just put what u have in the instrutions instead of mentioning temps thats what threw me.

thanks for that i'll let u know how i get on.

i did what u said tightbud & had to calibrate it to 6.68 then i put it in the 4 solution & had to calibrate it again(only slightly),surely this is gonna knock out the first calibration, anyway i think i nearish with it now.
god why i never bought 1 of these years ago i do not know i think i need a trip to the optitions because the readings i was assuming with the liquid ph testers i was well of the scale.
just cant wait now to get my next hydro grow on the go.

thanks again tightbud.

TBH i only calibrate mine to the 6.8 now(well 7 actually as thats the fluid i got)

but i'm sure that when i used to do both after doing the 4.0 ,and then putting it back into the 6.8 it would still read 6.8

rubix...you did calibrate it to 6.86....amd not 6.68 ...as your last post mentions ?

erm to the value on the buffer solution bottle i think got me thinking now .
but i now know what to do when the time comes to use it which should be soon.
got 3 mazar on the go took cuts of each waiting for them to root then gonna flower them as soon as they root to see if i have at least 1 girl.
then i want 10 cuts to put in my nft system.