If your pump is clogging up at the intake, and is submersible, what I did with my pump was get one of those plastic plant baskets, cut a hole/slot for the cord and the flexpipe to exit, set it down on a flat raised brick, and set rocks at the top so it didn't move. This allows only the smallest of pieces in, and promotes waterflow just fine. I am sure that eventually it can clog, but I dont see how it will do it from 4 corners that quickly - because of the direction the suction comes from. So far that has given me plenty of flow, and the solution took about 5 dollars. Everything else I tried, clogged quickly. Putting a prefilter sock, just meant that had to be cleaned. Every pre pre pre pre whatever at the start of the chain has potential to clog and take the rest of the chain to a halt.
Unfortunately you may need to bite the bullet if you want a functioning solution, and sometimes you can run into the case where youve decided the outcome by deciding NOT to spend what it will take to get the problem solved. But until you determine that its better in the long run to get the right tool for the job, and spend/save what it takes to get there, maybe the plant basket, or two Strainers/Collanders flextied together like a "cage" will get you by.
Sometimes there are soultions which dont require that you spend anything, but when those are exhausted without effect, you have a choice to make, fix it or let it go.