You emailed me indicating you intended to change your sand. That is probably NOT needed; all the pool books notwithstanding, we have seen NO evidence that sand 'wears out'.

Instead, simply (a) make sure the filter is FULL of sand, to the correct level, and that (b) the flow is throttled back. You can test this by checking the backwash. If sand is coming out, the flow it too high. (There will be a little sand on the FIRST backwash, and that is normal.)

One point to check though: there is some bad or fake filter sand out there. Buy LABELED pool filter sand (but not Quikrete pool sand). Before you add, grab a sample from inside the filter and compare it to the bagged sand. If the sand in your filter is coarse compared to the filter sand, replace it to within 1 -2" of the laterals. But if they are both the same, just add more as needed.