I have a standalone spa and noticed I am getting a brown slime forming all over the handles and on the bottom of the cover. This is only happening in areas outside of the water. Anyone know what the cause is (I have read High PH) and how to get rid of it and prevent it from happening again? Hot tub does not get used often right now but when I check PH it is always in line and bromine is good (Although it dropped to 1) once when I forgot about it.