Sand coming out of waste pipe when backwashing

[Charlieg]

Hi - I notice a small amount of sand on the driveway every time I backwash so have a few questions:

1) Is that normal?
2) Over time I will need to replenish the sand. Can I do that myself by removing the top of the filter and "topping it u" or is this a job for a professional only?

Thanks

[Walter]

if it is just everytime you backwash i would think it is okay unless it is a large amount, what is happening is when the sand is being churned in backwash it is going into stack pipe and being pushed out which is fine. As for adding sand anyone can do it, it should be about 3/4 full but make sure you cover the stack pipe opening up before adding sand.