Need any and all knowledge

[beaglelax]

I want to learn about sand filters what are there purpose and why do i always see them on big aquariums but there is non for small home aquariums so im just putting it out there what are they and what purpose to they serve and could serve us in the future

ty
beagle

[dc_909]

Sand filters are used to house beneficial bacteria on a large scale.

[beaglelax]

would they serve a purpose in a home tank , for reefs or anything ?