Filter For 20G Reef Tank

[ChaseO]

New to saltwater aquariums, I have had a freshwater aquarium before but want to get started with salt water aquarium. I have a 20 gallon long aquarium. I want to get a filter for it, that will be suitable for corals in the future anemones, and fish. I don't want to spend over hundred and $120 maybe even less than $100. I have heard all different answers for any type of filter but just not sure which one I should get. I would prefer not to get a refugium because they are very expensive, but I have heard hob refugiums work well. I heard canister filters aren't great neither are HOB filters. So anybody who could help me with any type of filtration would be great. thanks!

 

[targett]

As far as i know you dont need a filter, your live rock does all your filtering. Id say prob 10kg of live rock in that tank, as my tank is 125l and ill need 13kg of live rock

 

[Donya]

See these threads if you haven't already looked at them: Marine FAQ and Hardware List
 
As targett said, the live rock will be your filtration in a reef tank so the main concern beyond that is flow - which is best created by powerheads rather than HOB filters and such. For marine tanks, HOB and canister type filters, if used, are most useful for chemical media like carbon or storing extra rock rubble. Sumps are usually preferable to HOBs and canisters. Refugiums are not really filters; they serve as nutrient sinks when stocked with macroalgae, but they do not replace live rock or power heads as serving as a tank's primary filtration.
 
Anemones are generally advised against in tanks this small, particularly for a first marine tank and since you are also stocking corals (likely to have turf wars even if you wait a long time before an anemone).