What is the best leak detector to buy? I've been looking but just haven't bought one that I have been impressed with. One that has been successfully able to find a leak on a small system such as a reach in freezer/cooler that is low on refrigerant. The latest disappointment was the fieldpiece SRL8. For prespective, I was in a market and it was going crazy on a section of a meat case. Later that night when the case was emptied another tech, was there and didn't find anything. It was only a cheese case on a LL solenoid that we both found something. What do you recommend?