The salty air didn't come to mind. Looks like an on going maintenance program like you said which means $$$ in your pocket! Good job Erich.I did . It's a perfect cocktail of ground moisture mixing with salt air (it's in Malibu on a cliff). Instead of acid washing we used high heat @around 1800 psi. That removed 95% if deposits. We are going to do maintenance cleanings during the year.
Also going to apply a penetrating sealer. Did a test area with salt guard penetrating sealer and it tends to darken the stone. We will see..
Sent from my iPhone using Tapatalk -