Ok so I think I got a conclusive answer on pH and temperature proportions. I went to the local nursery and they have these premade pH and ppm bags with accurate already known levels. This is how you check your meters, and calibrate them. On these bags, they have temp scales, and with pH, a range of 32F to 120F, the range difference in pH is only 0.15 total. So the 20-30 degree difference from tap water to room temp is negligible.