Last night I did a trial run with my new 15.5 gallon keggle, march pump, and plate chiller. Everything worked like a charm. The pump pumped, and the plate chiller brought 5 gallons of boiling water down to 65 degrees in 5 minutes. as I was cleaning up I noticed that on the inside of my keggle on the very bottom there were tiny dark spots, which looked liked rust spots. Has anyone had this happen before, and will I still be able to us my keggle?