Here is my 20 long. 150 watt VHO in a CSL PC hood. Live rock and live sand are the only filtration. I change 2 gallons a week using oceanic salt. Very stable, although I seem to have a constant minimal amount of cyano on the sand, but im cool with it. Its a mixed reef consisting of softies, LPS, and SPS. Here is a list of inhabitants.
Fish:
Tomato Clown
Firefish
Yellow Clown Goby
Inverts:
2 peppermint shrimp
feather duster
several various snails
Soft corals:
hairy mushrooms
capnella
xenia
two different types of pink zoos
big green zoos
toadstool leather
green ricordia
GSP
LPS:
open brain
hammer
torch
bubble
SPS:
green monti cap
orange monti cap
purple montipora digitata
pink birdsnest
pavona
redish orange acro
and a purple acro with green tips
and some yellow one, not sure what it is
candy cane