Mask for spraying SH?

Does anyone have a suggestion for a mask to use when spraying house wash and roofs?

John Somers
Aqua Clean Pro Pressure Washing

All day everyday.

3M Particulate Respirator 8576, P95, with Nuisance Level Acid Gas Relief (Pack of 10): Industrial & Scientific

There are better masks than may be beneficial when on a roof but the one listed gets worn all the time because it is just so comfortable.

When do you replace the mask or can you use them over ?