false floor retf

[moe]

Hello. Any links to this question. Building a false floor for red eyes. Water, crate, screening. Any certain type of gravel then soil?. I built one years ago and use clay balls that helped clean the water and I used a filter. Can't think of what the balls were. Thanks

Do you run a filter to keep water clean in the false bottom. How high do I fill so the soil don't dirty water.