Low KH, GH and TDS....Still High ph

[halvyt]

I run a merlin ro unit and I throttle down the reject line to save on water. My water parameters from the unit is as follows

ph...7.24
KH..3
GH..3
TDS...64

I know that the ph jumps up to 7.65 after a few hours in the tank due to the CO2 being driven off but what gets me is why even after I add the peat moss brew does my ph stay the same?

 

[neosh]

Your pH will only drop after the KH is depleted.