” How to tell its time to change your pool filter?”
The word of thumb is to change your cartridge filter every two years if its a private pool. For a rental property pool, you should replace them every season. Before you do you will want to do the spring opening with the old filter and get the pool just right. Then go ahead and replace with a brand new filter for the pool season.
For D.E filters you will need to clean out the grids every fall at closing. Then come spring after you get the majority of junk cleaned out of the pool. You will get it charged up for the duration of your pool season. If you have a D.E. filter on a rental pool, you may have to change more than once a season to keep up with the demand renters put on your poor pool.
As for a high rate sand filter you can get away with every 8 years for a private pool, and every 5 for a rental. The way to tell if your pool filter needs to be changed is low flow or cloudy pool. If you have recently backwashed your sand filter or cleaned out your cartridge filter and you still have cloudy water. This could be a sign it’s time for a change. Same goes for a D.E. filter, but with a D.E. filter you will need to pull the screens rinse them, then recharge with D.E. powder.
Make sure to read directions or youtube how to clean out and replace new media in your filter. Remember pool filters are under tremendous pressure and can be very dangerous if opened while running. They can also be under pressure just from gravity, if the pool is higher than the filter system. Don’t be cheap replace all the gaskets on your sand filters at time of change.