How do you know when you need new sand in a Hayward filter for an inground pool?
Depending on the size of the pool and the size of the filter and the amount of times you have to backwash, also if you have had a lot of rain then you may need to backwash more than usual. If you put the pool in and the filter and you know how old the sand is, if you are backwashing more than usual,change the sand. Also before you backwash check the pressure of the water going back into the pool, then backwash check the pressure again the pressure should for any size hayward pump push your hand away if it does not then change your sand.
