Originally Posted by djlunchbox
The best option is matrix cubes, no rock. But that doesn't answer your question
Actually, it does. The old method of using progressively smaller rock as you backfill works fine for a while, but, depending on the location, it will eventually clog. Cleaning of these systems is a real PITA, that is why some bright engineer somewhere came up with the concept of matrix blox. Same final result, less future and continuing maintenance.