Re-doing all supply in my remodel. Using pex a as recommended by many. It’s all completely in, used the professional Milwaukee expansion tool for all manifolds and fittings. Now air pressure testing and using soapy water to find any leaks…I am getting small bubble builds in areas…these areas are on their second rebuild because they bubbles the first go around. This second time I used a heat gun to ensure a tight fit. I am at a loss since this is the second round and I am still seeing bubbles under pressure. I have asked a couple plumbing stores and professionals, they all have said to use water…I truly don’t want to cut and couple any more lines at this point…is the issue that I am using air and not water?