It may speed up tarnishing on your RG, but I don't know what is in the cleaner. I would HOPE that whatever it is wouldn't be an issue.
I've found the instruction booklet of the cleaning gel and these are the ingredients:
Water, Sodium Laureth Sulfate, Sodium Chloride, Methly Chloro Isothiazolinone, Methyl Isothiazolinone
What do you think - harmful or not?