Very, very smart! Well done! (Pun intended )

Try adding a little bit of DE powder to your sand filter, through the skimmer or the drain if it doesn't have a skimmer. Do it just after you back-wash. Since it's a smaller pump and filter, start with 1/4 cup, wait 1/2 hour and see if the pressure goes up. Repeat until it goes up 1lb of PSI. This will add to the filter's ability to get even finer stuff. 10# of DE usually can be had for about $8-$10, and will last a sand filter owner several years, at a minimum. Every time you back wash, add the amount you determined raised PSI by 1#. And, if you have a skimmer, get some skimmer socks, which are now (as of last Thursday) about $5 for 4 of them. You can rinse and reuse them until the elastic goes.

All this may help.

Carl