Went out to check out the pool the other day and noticed lots of corrosion on the leading edge tube where the grounding strap screws to it. Checked other side and grounding screw has come out. Opened lid down by the motor and found lots of corrosion on the tube the cover winds up on. Do I have a grounding problem? Stray current? Called pool builder for another question and still haven't gotten a call back since early last week. Pool is 4 1/2 yrs old. How do I check for stray current? Would post picture but I cant figure out how to post it.Thanks