Newbie with a PH sensor

Hi, totally new Arduino so sure this is my dumbness kicking in.

Got a MKR 1010 and a sen0161. powered from my Mac usb.

Using the code on the DF robot website (PH_meter_SKU__SEN0161_-DFRobot)

I can't seem to get the correct reading. When I short the BNC I get 2v 7ph. I don't need to change the offset.

When I use 4.01 or 6.86 or a 8ish ph water the value over reads below 7 and under reads above 7.

4.01 liquid = 1.48v 5.19ph
8ish = 2.09v 7.33
6.86 = 1.95v 6.81

I can use the gain potential to match the reading when in the 6.86 liquid but not the 4.01.

VCC to power on adapter
grd to grd
data to A0

It seems the calculations are incorrect in the code but not at that level to recode it and figure out why?

I did also put the adaptor power to 5v on the MKR1010 was getting 12ph numbers.
Thanks if you can help, much appreciated


Any one?
Please and thanks

I have messed with analogue read resolution 12 bit for the mkr board but still nothing making sense.