I purchased my house about 3 years ago. It has an in-ground pool that was built in 1980. It has a sand filter, which I believe to be a Hayward S200. I can't find a model number, but it looks exactly like the pictures I find online. I have no way to be sure, I believe that this is the the original filter, which makes it over 30 years old. It doesn't seem to filter very good and I suspect that the sand may be caked and/or channeled. So I was planning on taking the top off and doing the garden hose thing to break up and clean the sand.
Is it possible that this filter still has the original sand in it? Is there ever a time when you'd want to change the sand? I'm only asking because if I'm going to go through the trouble to unbolt every one of the 24 bolts to take the lid off, it might make sense to do a complete sand change instead of trying to clean the old sand which could contain god-knows-what and might not even come totally clean.