I need help. I have an enclosed patio with old saltillo tile. Lately like 3 or 4 weeks ago there started to be a growth on some of the tiles. It is white. I cleaned the tile s with a clorox solution and it came back. yesterday i made a chlorine solutiona and scrubbed each tile with a sponge. By this morning the white growth was back. I recognze the tile needs to be reesealed but i need to kill whatever is growing first and I am out of ideas