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Does the speed of flow over the biological filter affects it effectiveness ? I was told that if the water flow is too fast, the biological filter is not effective.

That does and doesn't make much sense.

A. Increased water flow means more oxygen for the bacteria. More oxygen should mean more bacteria can live.

B. Increased flow doesn't allow the bacteria to eat what they need to from the water waste, to maintain good health.

*shrugs*

Good question..

Last edited by Shannen at 02-Mar-2005 10:06

Hi,
Actually, I suspect that the folks who designed your filter
(assuming its not something you built yourself), had all
that in mind when they selected the pump, the size of the
chambers, the quantity and types of media, and the overflow
system. As long as you operate it as designed, it should
work quite well. If you change pumps to one larger, or
you remove media and don't replace it (reduces the
resistance to the water flow and as a result the flow is
faster), then you are changing the characteristics of
the system, and perhaps the efficiency might suffer.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

I think my overhead filter is only for mechanical filteration. But I add a layer of bio rings for biological filteration. However, I think the flow rate is too fast. Do you think it is a good idea to reduce the flow back to the tank, ie I sort of flood the filter box so that the bio rings are semi-submerged in water all the time.

Hi,
I suspect "we" might be getting into an area of the English
Language where we can say the same thing differently.
The ceramic rings, or "bio balls" were origionally designed
for use in a "trickle filter" where water was trickled over
them collected at the bottom of the chamber and then
returned to the tank. Generally the water was not "poured"
over them, but rather trickled and yet, not dribbled.
I think you sense my usage. If you are flooding them then
they are not necessarily working correctly.
Perhaps the best way would be to look at a properly working
filter that uses "Biowheels." Notice the time that each
vane is exposed to the air, and the relatively short time
that vane is exposed to the water. That kind of ratio is
generally the idea in a trickle filter. You want to keep
the rings wet, and at the same time exposed to air.
The thought is that if you have the water cascading across
the rings or balls, that you will have more surface area
exposed for bacterial colonies, in a given area, to
thrive and purify the water.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

I think it depends on the physical setup of the filter.
I know Eheim is bigger on biological filtration then some of the other cansister brands. Eheim's flow rates are alway less then their competitors, but are rated for tanks just as big because of their claim to greater biological filtration.

My Scapes

Sounds logical that water are supposed to trickle over the bio rings. In fact, that is the setup I have seen most of the time. However, I have also seen internal filters with wool and bio rings. So I don't know if this type of internal filter is effective.