20 Gallon FOWLR - New Setup

[jpcemc]

I am considering setting up a 20G FOWLR (and iverts) tank and I have seen some posts saying that an external filter (canister) is a waste of time and to use two powerheads for gas exchange but I worry about having no media. I have seen that the live rock and sand is sufficient filtration when there is a very light bioload (2 clowns, shrimp, urchin, etc). Any truth to this? I have a 40G with a 20G sump and a very light bioload and I still get nitrates, and phosphate - which I know are necessary for the coral, but still.... So I worry that a 20G with no media filtration would suffer. Insight?

Thanks!

 

[jpcemc]

This is my 40 - please dont mind the crappy rock setup. My fish love it and the tank is very healthy so I dont mess with it.

https://ibb.co/chMVgk8

 

[101010]

The Live rocks themselves provide a lot of surface are for the biological filtration and in case you have sufficient LR in your tank( which most likely be looks like) no other bio media is required, it may take a while for the rocks to harbour sufficient Bacteria but it should eventually reach an equilibrium. The use of filtersocks, skimmer as a physical filtration and nutrient export with macroalgae and water change will also help.

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