Hi, I am new to gardening and I am interested in planting blueberries in my backyard. I did a bit of research online and found that they like acidic soil, pH around 4 - 5. I also read that an easy starter is to mix regular potting soil with peat moss, in a one-to-one ratio. So I did that in my 20" pot, but when I use the commercial pH tester (the one with 2 needles sticking into the soil) it says pH is only 6. In fact, over time, it appears the pH is gradually returning to 7. Is my tester broken or is it expected, that the peat moss wasn't acidic enough? I did my initial gardening shopping at Canadian Tire, and the next acidifier available there was aluminum sulphate, which many people obtained due to the toxic aluminum. Any advice and tips? Will my blueberries grow fine with a 1:1 mix of peat moss and regular potting soil?