Tropical Fish Forums

[BPH]

I really don't understand how canister filters provide oxygen to an marine aquarium... I use a fluval 205 canister, instead of using carbon(which I thought provided the oxygen) I now use 3 layers of fine pads and 1 tier of bio balls, and the 4 large paddings. so how does the canister filter provide oxygen?

[Topper]

It may be different for a marine tank, but I don't know of any canister filter that provides/creates oxygen. The bacteria in a biological filter need oxygen to survive - but it gets that from the water. Moving water (surface agitation, power heads, etc.) will certainly provide more oxygen as the surface area is increased, but the filter itself moves the water to gain this ends. It doesn't create extra oxygen in the canister itself. Any filter that is run with a pump (corner bubble, under gravel) will increase the oxygen as air from the pump is introduced directly into the water column.

So in short, by moving the water the canister filter increases the oxygen - it does not provide it.
_________________
You're gonna need a bigger boat...

[Osprey]

Yup, that's how it works. Dissolved oxygen levels tend to be lower in SW, and many of the critters in our care require increased water flow, so in addition to filters we usually add powerheads to make sure there's enough oxygen in the system.
Carbon has no effect on oxygen; the purpose of running carbon is to remove impurities and dissolved organics.
_________________
Am I obsessed? Wait a minute... don't answer that!