Hey guys I'm think of having a 20 gallon nano, how much live rock would I want for that size? And if I had adequate live rock would I need filter? Thanks
The rule of thumb is 1-2 pounds per gallon of water. I stay around 1lb/gallon as not to have a tank overrun by live rock. A filter, especially refugium or sump, is always a great idea.
You can use dry rock (Look into Bulk Reef Supply or Marco Rocks). And yes you need a "filter". Don't use a freshwater canister filter. A protein skimmer is the main means of nutrient export in this hobby. I recommend looking into one.