Overboard on a filter? is it possible?

[Wiggs]

Is it possible to go overboard on a filter? say using a 30gallon filter in a 20gallon tank?

Reason I ask is that the price difference seems to be very minimal. Is this a common practice? or just a waste of a few dollars? more importantly, are there any drawbacks to doing this? I can't imagine any, but best to know for sure :P

[Sharkman]

that would be fine. It is reccommended that we use a filter that is rated for a tank size slightly larger than the size tank you intend to use it on. The only way I think there would be too much filtration is if the fish look like they are constantly swimming up stream or struggling to swim. I think you will be fine with that size.

[nwnittany]

I've read in several places that it's a good idea to de-rate the filter manufacturer's claims by a factor of 2. In other words, pick a filter that's rated for a tank twice the size of the one you are buying it for.

Another strategy is to buy two filters, each roughly rated for your tank size. This way you don't have a single point of failure and have a seeded filter if you ever decide to start another tank.

The only negatives I've heard about having 'too much filtration' are a) it costs more, and b) it can create too much water flow (not really a case of 'too much filtration' but more a case of 'too much water movement').

[Wiggs]

Thanks for the info. I'm going to see what happens, even though i have the 20gal, I may be moving up to a bigger size as a friend of mine is getting out of the hobby and his 40gal is a possiblity. I'll just have to let the cards fall into place and see what happens.

[KINGMED]

I use an AC110 FILTER on my 29 gallon, they are supposed to be rated for 55 gallons and it does a wonderful job. Therre is a little current but I turn it down quit often and I turn off the filter when feeding for a short time so they can eat in peace.

[Fishguy2727]

I generally cut whatever it claims in half, this is about what a filter is worth on a medium stocked community tank. With higher bioload fish like goldfish and cichlids I add even more filtration. So for a 20 I would have 40-60 gallons worth of filtration.

You can't have too much filtration, but you can have too much flow. Even too much flow is pretty hard to achieve though and is evidenced by the fish and their behavior.

[cichlidfever]

the two filters i'm using on my 55gal are "rated" for a total of 160gal. depending on the kind of fish you plan on keeping, you may NEED a bigger filter.

[bushwhacker]

for me double the filter for your tank size is a bare minimum triple would be even better