How do you change sand in Jacuzzi filter?

turn you multi port valve to back wash before starting filtration.

If your pump is throwing sand back into the pool from the filter, you more than likely have a cracked or broken lateral (finger). To check, remove all sand from you filter and pull the center pipe and laterals out of the tank and check all pieces to make sure there are no cracks. If a crack is found, replacements can be purchased from you local pool store.

Or:

You did not cover the stand pipe at the top of the filter. Try backwashing a few times and monitor the amount of sand returning to the pool. If there is less coming back you may not have to do much more. If it continues but only slightly diminished then you may have to remove the sand, remove the stand pipe, check the laterals for broken parts, replace if needed, clean the area at the base of the laterals where the stand pipe threads in, install the stand pipe, cover the top opening of the stand pipe with tape or a plug, add water to the tank - to about half full, then add the #20 silica sand - no other grade sand will work. The rest -- you already know how to do.

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