Why isn't it necessary?

It's unconceivable to have a freshwater fish tank without some sort of mechanical filtering going on. I don't see much talk about mechanical filtration with reef tanks, though. Is it not necessary? Is it the cleanup crew that handles the mechanical filtration, or am I mssing something? I'm planning on using an Orca Profuge that uses filter socks. Is that all that will be necessary?

Thanks,
Steve

 

We don't typically use wet/dry filters etc.
But instead we allow everything to be broken down naturally by fish, coral, CUC, and bacteria.
As far as additional filtration we usually use protein skimmers to remove organic molecules, some people use macro algae to soak up nitrates and phosphates, media reactors filled with bio-pellets or GFO, and occasionally nitrate reactors.

 

I think that in freshwater tanks, the filters, be it internal or external cannisters
are the primary source of bacteria accommodation, and thus in actual fact become biological filters, in addition to the ability they have to trap debris that you can remove by cleaning the media in tank water ( you use tank water in order not to kill of that much needed bacteria)

In a reef tank, the amount of rock that we typically utilize eliminates the need for any additional real estate for bacteria to colonize and as such most reef tanks do not need additional canister type filters

fish only tanks with large predators that need a lot of swimming space, are an exception IME, in that you do often need a source of additional media for bacteria to colonize because putting enough into the tank, hampers the fishes ability to maximise the available space

 

+1 to Steve and Dingo's posts. Also the filtration we use in reef tanks also removes the suspended particulates in the water.

 

Thanks for the replies. That helps me undstand this much better. So a balance of critters, plus optimal live rock, and algae in the refugium all together replace what is typically a canister filter on a frewater system?

 

That's a fair evaluation. A freshwater tank doesn't have janitors available, which includes not only the snails, hermit crabs, etc but also many micro- and macroscopic critters that come in on live rock and sand; Therefore, uneaten food and waste must be trapped by a mechanical filter for removal.