Early in 2007 I replaced shutoff valve and supply tube to upstairs toliet. Lately I have noticed a white powdery substance on the valve and tube where they connect also there is a greenish color at the compression fitting where the tube enters the valve. No moisture of any kind is currently present on the valve, tube or floor. It is possible at one time there was and now it has sealed its self. Do I need to do anything with this or is it ok?