I have recently extended some pipework using compression fittings. It had
been suggested to me that I should not over tighten the fitting as the olive
could cut into the pipe. Now I have notice on a couple of the fittings that
whilst they appear water tight there seems to be a powery deposit forming
round where the pipe goes into the fitting. It suggests to me that I have
not tightened them correctly but would appreciate any feedback.

Thanks

David - Milton Keynes