M Waisman wrote:
Do you mean ethyl alcohol or hydrogen peroxide, by chance? i don't see ethyl hydrogen peroxide, even on Amazon.
Regular Hydrogen peroxide reacts with catalase. Catalase is needed because it is the enzyme that makes this all tick, and it is all natural. There are two types of hydrogen peroxide: 3% and the stronger 6-10%. Either would be fine. Since the pee is in the grout of your tile, I would make sure to get this catalase (powder) over any area that has been peed on, and then trickle the hydrogen peroxide (liquid) over that powder. If that saves your floor so you don't have to break out your tile and redo the whole floor it would be worth it.
The cat is naturally going to want to pee wherever she smells another cat, especially if another cat peed there. They mark their territory that way. Your cat knows this is her territory, so she is just making sure to keep out the riff-raff by spraying that area. Once the uric acid is broke down, and hopefully gone, then you stand a chance of your cat no longer feeling the need to mark the spot as her territory.