That's exactly why a sediment trap was mentioned, to stop it ending up in the tank.
As long as the pipe that drains the system is at the low point and the T piece to that drain pipe points down, before heading off away to a good draining spot, then any sediment will get trapped in it and get dumped/flushed when the system is drained.
No need for diverter valves and switching them over when it rains.
If it hasn't rained for a week or two in the summer drain the system and put the cap back on. If rain is due in the summer check the gutters and leaf baskets are clean.
