After the installation of Keratrax MS your surface will need minimal maintenance.

If the droppings are picked up regularly, it will remain in good condition. Dropping disintegrate into dust and mix with the surface materials, once wet the droppings will turn into a paste consistency and mix with your arena surface.
The surface will last much longer if it is levelled and graded on a regular basis to ensure the surface materials are turned over and aerated.
Some indoor arenas may occasionally need watering in hot weather, as soon as the moisture is replaced, the surface will retain structure.

Other materials that are brought into the arena have a detrimental effect on the surface materials. The best way to prevent this is to pick your horses feet out before you enter the arena, try to avoid mud before entering the arena. If the arena is situated next to a tress or hedge that drops leaves, ensure they are picked up before the horses stand on them and work them into the surface.