So if your pen is reading very low and you are using P/Carb, your pH is likely through the roof and leaving residual saltsMy Pen is dog, room temp milk (not expired) its at 6,1 are there any other ways of testing ph without a pen? (I Know Strips are unreliable)
Flush the pot with distilled or de-ionized water then feed as normal but skip the K/Carb , it's not necessary in soil anyway
Sounds like your meter is nearly a whole point out, but now you know that you can deduce the true value
ie if you know a clock is 1 hour fast you can still tell the time