Filter spitting out sand?

[Poconos]

First, welcome to the forum.
The 300# model may be an S-244T same as mine. It is normal to get sand out the waste line when backwashing as there is nothing in the filter to prevent this. In time the amount you get dumped will decrease. The procedure should be to backwash until the sight glass is clear, then rinse for only 15 seconds or so. Rinse mode is the same as Filter except the output is directed to waste. Any stuff stirred up during backwash is dumped to waste instead of back to the pool. The things on the bottom are called laterals and are simply pipes with slits that let water flow but prevent most of the sand from dumping. The sand should be labelled Filter Sand or something like that.
Hope this helps.
Al

[JohnnyK]

Well there is quite a bit of sand below the jets, but it seems to have stopped for hte most part of coming out.. I think.. I should go check again. But is it normal when changing sand (or whole filters for that matter) that there is a bunch of sand that is too small and gets blown through, or something to that effect?

[nicole12]

I also changed my sand for this season. The first backwash I too got about 5 lbs of sand on my lawn. From what others have said this is normal. Also I have some find sand/dust at the bottom of the pool that came from the return that some also say is normal. Most members recommend vacuuming that to waste or putting about a cup of DE in the filter vacuuming and then immediately backwashing.