u/Deep_Flamingo5425

Heys guys first time poster. I would really appreciate if someone could help me. I ran into this problem with these rust stains on both Italian ceramic tiles and also on stucco. I used F9 barc on both already but it didn’t do anything. The owner said that the house was very recently built so it’s been around 4 months since it could have happened. I was about to buy Mar Gel Oxi Kit because I heard it works but I thought I would ask first. Does anyone have any idea what I can do? Any help is appreciated. Thanks!