What type of sand and how much for my Hayward GM 245 sand filter ?

SOURCE: Does the Hayward GM-245 Sand filter tank separate

I am not that familiar with the G series Hayward filters, but most sand filter tanks do not separate. It's a labor intensive job so think hard before trying it if you haven't before. If your backwash valve is on top of the filter, the plumbing will have to be removed. There are two ways that I have removed the sand. Scooping it out by hand or using a shop vac. Remember the sand is going to be very heavy when wet. You will need to go through the top. Some filters have a large drain plug in the bottom that "supposedly" you can drain the sand out through.I have done this once and it makes a big mess that you still need to clean up.

Be sure to buy replacement o-rings and gaskets as needed. There is also a product called a sand vac that is in essence a siphoning system.

Be careful not to damage the laterals it the bottom of the filter. When replacing the sand, I put small gravel (pea gravel) carefully under and partially around the laterals to help support them from the weight of the new sand.

When you are done, be sure to backwash the new sand to remove dirt, impurities, etc. This is a general overview. There are books online that give more detail or use a similar filter's manual...