Every time I try to recrystallize a white marble floor, located in a bank lobby, it turns gray. This has been happening over the past several months. I don’t have any other problem with white marble except for this one bank lobby. Can you expla

It sounds like there may be a moisture problem in the bank lobby. The recrystallization process does not work well when moisture is present. The gray you are getting is the result of moisture reacting with the steel wool and the recrystallization fluid. Check the floor carefully for moisture. I would highly recommend purchasing a moisture meter. If moisture is present you will need to try and locate the problem. Has the floor been flooded with in the last six months? If so it may take several months to dry. There may be a leak somewhere that the bank is unaware of. Until the moisture is located and eliminated, do not attempt to recrystallize. If you need to polish the floor you may want to powder polish only.