Black dust coming back in from Water return

[BcCarr]

I have noticed I have fine, black dust on the floor when filter is off in morning. I use a vacuum, not connected to pool or filter, and it cleans it up. However tonight, after kids swimming, I backwashed for about 1-1:30 and noticed a large amount of dark, dirty water coming back into the pool from the water return.

I have a sand filter, and replaced sand last year.

Numbers are all in good range. Thanks

[BcCarr]

Sorry I think I posted this in wrong section

[Teapot]

Have you given the filter a really good backwash and rinse?

[BcCarr]

Have you given the filter a really good backwash and rinse?

Yes, it’s a sand filter. I run it for about a minute to two minutes and then when I switch it back from backwash, I can see a flow of darker dust come back into the pool from water return. After vacuuming it up I liked in the catch and didn’t see any sand, so I’m assuming filter is not leaking

[Teapot]

That maybe too shorter time. 3-4-5 minutes on backwash and a minute on rinse. Hold a piece of printed text under the sight glass to be sure it's running clear. The first load of dirt comes out easily, dirt that is deeper in the sand can take longer the backwash clean

[BcCarr]

That maybe too shorter time. 3-4-5 minutes on backwash and a minute on rinse. Hold a piece of printed text under the sight glass to be sure it's running clear. The first load of dirt comes out easily, dirt that is deeper in the sand can take longer the backwash clean

Thank you, I’ll do that