Is having multiple filters OK?

[SA]

Is it ok to have two filtration systems in place on the same tank?

I am planning on setting up a 45gl tank (my very first one) and I purchased
a Hagen Fluval 204 canister filter. However now I am not sure it will be
sufficient for the tank... since I think it is only rated for 30gl. Should I
up it to the 304 or should I add another smaller canister for redundancy in
case of a failure? I was told that even though it's a 45gl tank there will
be less water in there because of gravel etc. is that how one is to measure
filter capacity?

I was planning on having around 20-25 small fish in it.

Any other recommendations are greatly appreciated since this will be my very
fist tank...

Thank you in advance.

Steve

[NetMax]

"SA" > wrote in message
...
> Is it ok to have two filtration systems in place on the same tank?
>
> I am planning on setting up a 45gl tank (my very first one) and I
purchased
> a Hagen Fluval 204 canister filter. However now I am not sure it will
be
> sufficient for the tank... since I think it is only rated for 30gl.
Should I
> up it to the 304 or should I add another smaller canister for
redundancy in
> case of a failure? I was told that even though it's a 45gl tank there
will
> be less water in there because of gravel etc. is that how one is to
measure
> filter capacity?
>
> I was planning on having around 20-25 small fish in it.
>
> Any other recommendations are greatly appreciated since this will be my
very
> fist tank...
>
> Thank you in advance.
>
> Steve

It is always preferable to operate using multiple filters (for redundancy
and to alternate servicing so the bacterial balance is less affected).
Although sold that way, filter size has very little to do with the total
volume of your tank. The tank volume to filter size is basically related
to a flow rate which will provide sufficient mechanical turbulence, and
will provide sufficient biological surface for a bio-load consistent with
a normal loading of the referenced tank size.

For example, a Neon tetra in a 100g tank would be very happy with an
Aquaclear Mini (from the view of biological filtration). Relate filter
size with the amount of food you drop into the aquarium. This is the
direct relationship. You can also look at your fish load and correlate
filtration requirements. If you are less familiar with this, then use
the 1"/gal rule for medium bodied fish, and when the tank is at capacity
(max. fish-load), a filter sized for that tank will provide sufficient
operating margin. Increase your fish load and you increase your
filtration to maintain a safety margin.

ps: maximum filtration redundancy is achieved by operating more than one
dissimilar filter (ie: powerfilter & canister or UGF, or sponge powerhead
etc etc). This better utilizes the strengths of the different systems.
Operating 2 canisters is still excellent (as canisters provide wide
spectrum mechanical/chemical & biological filtration). Your individual
filters would be sized for around 66% of the tank requirements, so with 2
filters, you are at 133% of capacity. This approximate ratio generally
doesn't give you too much turbulence, will easily re-populate your
bacteria (in the event a filter is nuked), and a single filter will be
strong enough to carry the full load during failure/repair of the 2nd
unit (just decrease your feedings, - remember the food to filter size
ratio). hth

NetMax

[Dinky]

Inline.


"SA" > wrote in message
...
> Is it ok to have two filtration systems in place on the same tank?

Yes. However, a Fluval 204 is, according to the packaging from *my* 204,
rated for 40 US gallons. As long as you don't overstock the tank, it should
be fine. Monitor water parameters accordingly. Have you researched
"cycling"??
http://faq.thekrib.com/begin.html


>
> I am planning on setting up a 45gl tank (my very first one) and I
purchased
> a Hagen Fluval 204 canister filter. However now I am not sure it will be
> sufficient for the tank... since I think it is only rated for 30gl. Should
I
> up it to the 304 or should I add another smaller canister for redundancy
in
> case of a failure?

If the 204 is still new, sure, I'd take it back and get the 304 is money
isn't a prohibitive factor.


I was told that even though it's a 45gl tank there will
> be less water in there because of gravel etc. is that how one is to
measure
> filter capacity?

The rated capacity is a guideline, no more. The number of fish, and how much
ammonia (excrement) they produce is the important thing. In a fish-only
tank, I like to get a filter thats slightly overrated, to compensate for
variables.



> I was planning on having around 20-25 small fish in it.
What kinds?

>
> Any other recommendations are greatly appreciated since this will be my
very
> fist tank...

Research. Read the aquaria FAQ I posted above.
Look into fishless cycling.
Don't blindly trust advice from a pet shop, particularily the big-box
chains. There are exceptions, as always, but ignorance and the drive to make
a sale will cause people to say anything. (ex: "There is no way you can have
live rock withot an undergravel filter.")



>
> Thank you in advance.
You're welcome.

>
> Steve


Billy

[SA]

Thank you all for your insightfull resonces. I will get the larger filter
for now and look into a backup unit in the near future.

Thanks again.

Steve