I am not sure this idea would fit your situation. Same problem. I my tank I had a plastic "filter basket" of about 8 inches in diameter that covered the tank outlet suction line. I used hot glue, silicone aquarium sealer and Gorilla Glue at various times...all of which are completely waterproof. Later I added a covering of fiberglass window screen. Of course, I had to crawl inside my 400 gal tank to do the work--but--if you arms are long. At the end of the year I had a sandy residue in the bottom of the tank, that I would clean out during the winter off-season.
On the other hand, drop by your irrigation dealer--he will likely have several types of filters that could act as pre filters in the suction line that you could install ahead of your fine filter. I used a 325 mesh fine filter --cleaned about twice per week.
Let us know how it works out. Or get a different supplier of SOP.