I have a customer that has limestone or sandstone paved pool deck. Large white pavers with natural shells and are smooth in places but also has natural porous areas all over them which hold green algae. They get algae a lot but this time around the pool deck area specifically under the bushes were large bright orange stains. I believe the deck is sandstone or limestone as there’s imprints of shells and natural impressions. I tried SH and then started using a nozzle which faded some of them but I felt that was not the correct thing to do as I didn’t want to damage them. I did not have acid on the truck but I have oxylic acid , sodium hydroxide or muriatic if needed. I’m thinking oxylic would work the next time I do this patio. But the question is what are the stains because I have another customer that started getting them on similar looking material. Are they limestone or calcium or could it be fertilizer? They are bright orange in color and the customer stated that they just appeared a few days ago. What could they be and how to remove them? sorry didn’t take pics.
Could be fertilizer stains ……see it a lot on sidewalks here. If fertilizer stains then acid will do the trick. I use OneRestore or f9 barc. Cleans up nice……
I recently returned to the customers and used oxylic acid and unfortunately seemed like it had no effect. I’m thinking that the stains are into the sealer.
did you wait until it was Dry to view the results after the oxalic? has to be dry to assess it.
Following this. I had a couple orange spots this year. They were from the grass guys getting fertilizer on the black top. We justed high pressure and brush and it came up. Not sure what we woulda done on other surfaces
I think I applied twice. The first time was using a sprayer, I think there was enough time to dry while I was doing the front driveway. Then went back and brushed some on. Didn’t stick around for that to dry.
