Basically, I am using 9 liters (3 gal) bucket, a little more than 2 capfulls (by eye). But basically, when I use it on a 95 degree 4PM (direct sunlight) wash of my BLACK car, I notice water marks on the paint that DO NOT get removed. Now, I decided to try and use No rinse on half the car, and the other half I used my cheap walmart car wash soap. It seems like the regular car wash soap worked better on the other side. Is this because of temperature? (or Black is a bitch, etc.) Are there any GOOD car wash mixes that are soapy and require rinse unlike optimum?