I am currently using the Berlin method for natural filtration. I have a FOWLR
/invert tank, but will most likely lean over to a reef down the road. Here is the information I got before considering the Berlin:
No undergravel filter. This will create problems down the road with nitrates.
You will want between 1 - 1 1/2lbs of lr
. The more the better.
You will want an excellent skimmer. You can't skimp on this one.
Since you have a 30G, you could setup a 10G sump to put the skimmer, heater, bio rock, etc. in.
You will also want at least 2 powerheads for water movement.
According to what I have read, there are two ways you can setup a sand bed. Either shallow, or thick. No in between. I went with the 1 1/2 inch sandbed on mine. Some people prefer the thicker ones between 4-5" sandbed for reefs.
With the Berlin method, you don't need a canister filer, which is what I used before setting it up. The lr
will be the intended filtration.
I do, however, use my canister to run AC
every now and then to polish the water though. It's good for that. HTH