I have a Futura SSA. Lately I've noticed its leaving a blotchy residue of wax or oil?on my vehicles when I test the wash. This happens only periodically and a couple weeks ago I thought maybe my wax was mixed too strong. I checked & It was mixing very strong so I tamed it down to where it is supposed to be. I still seem to get the residue once & a while. Could it be wax build up in the hose? My pumps do not seem to be losing any oil so I don't think its that. Any help would be appreciated.