If you’re using sand as a substrate, you’re using power filters, and you keep destroying filter impellers because of the sand, you’re doing something wrong. I regularly hear of hobbyists claiming they can no longer use power filters because of impellers getting fouled by sand. Even if your tank is stocked with sand sifter cichlids (e.g., eartheaters like Gymnogeophagus or Santanoperca species), using power filters should not be a problem.
The solution? Raise the filter intake. This will resolve the problem 85% of the time. The other 15% can be resolved by prefiltering your intake. The closer the intake to the bottom of the tank, the more likely it is to pick up detritus and other material, which includes sand. Why? Because sand and most detritus are negatively buoyant, which means they won’t float. Anything that does gets stirred up won’t rise too far. If your maintenance routine includes regularly vacuuming the substrate, there shouldn’t be enough detritus to require a prefilter, so just raise the intake a few inches or until you stop getting so much sand in your filter.
All of my tanks have sand substrate except one. Of those with sand, I have a total of 7 canister filters and 2 HOB filters running. I have some intake tubes 4 or 5 inches above the sand, but all my intakes are prefiltered. I have never lost a single impeller because of sand. While prefiltering won’t eliminate sand from getting into the filter, impellers can easily tolerate some sand. Every time I clean my canisters, there is some sand in the bottom, but no more than a tablespoon total.
There are many ways to prefilter, but my favorite is using sponges. Other popular methods include tying panty hose to the intake or even using a cut-to-fit media bag. There are others options, so use what works best for you. You just have to be careful to not decrease the flow intake too much with whatever prefilter method you use.