Can You Over Filter?

[Tropical_Fish]

I've read a few topics about filtering and the recommended amount to filter is 5x the capacity of the tank. My tank is 70L so I need one that provides atleast 350 L / hour. Having read more I found that you should factor in 20% as the rated amounts are maximums. So I really need one that will do about 400 L / hour.

I've been offered a cheap fairly large filter which says it does 1000L / hour - would this cause any harm from over filtering. Is it worth using? I might just sell it on to buy a more suitable one.

Any thoughts?

 

[cowboy507]

in short...NO
much better to be over filtered than under. this will hep prevent algae growth also

 

[Tropical_Fish]

Does it cost much more to run a 1000L / hour than it would to run a 500L / hour? ie does it cost double to run?

I'm not sure how much power a filter uses. The 250 L/h one uses 3.3W so having that on 24 hours a day is only like having a 60w lightbulb on for roughly an hour.



I've just looked it up and the 1000L one uses 12w so it is roughly proportionate. So a 1000L filter would cost roughly twice as much to run as a 500L filter.

For the 1000L it will be like having 4 additional 60w lightbulbs on for an hour - so not terrible

So kind of answered my own question there!

 

[waterdrop]

This question comes up periodically and its a bit of a trap question. Its perfectly true that you can pretty much never have too much "media volume" (mother nature has practically infinite when you look at the size of a swamp or watershed compared to a fish) but flow rate is altogether another thing. Get too much flow for the tank size and you've basically got a 'lectric washing machine on spin cycle ... now I hasten to say that there are things you can do (point the spraybar holes at the wall (that's the tank wall, your wife won't want it on the room wall)) but if you consider that the planted guys like to churn their tanks with 10x and higher, you can see that its certainly done out there! Its a balance between all these good things (big filter boxes, no dead pockets to promote algae) and the potential loss of fish looking peaceful that got you in the hobby to begin!

Ah, I should write more but I'll shut up...

~~waterdrop~~

 

[drobbyb]

I run 12x an hour with a powerhead and my fish have no problems. I agree that you can't really overfilter, but I wouldn't go above 15x an hour.

 

[Tropical_Fish]

I run 12x an hour with a powerhead and my fish have no problems. I agree that you can't really overfilter, but I wouldn't go above 15x an hour.

it would be approx 14.25x per hour so close to your limit

I think I'll have to test it and see what it's like - if it seems to big I'll try and sell it to get a fluval 3+ or swap it

 

[aaronnorth]

I run 12x an hour with a powerhead and my fish have no problems. I agree that you can't really overfilter, but I wouldn't go above 15x an hour.

it would be approx 14.25x per hour so close to your limit

I think I'll have to test it and see what it's like - if it seems to big I'll try and sell it to get a fluval 3+ or swap it

there isnt really a limit unless your fish are pinned up against the wall! I currently have 18x turnover, i have seen people with 32x turnover (and that was in a 60l!)

 

[AdAndrews]

theoretically i should have about 17x turnover in my new 35litre nano, however i probably will only be getting about 10, i am using a 600lph external btw.

 

[Tropical_Fish]

So from that, I might actually be able to use this one,

I'm not sure how good they are - I've read some bad comments, and some good comments.

It's a fluval 304 External which I got with a pile of other bits - so providing it works ok, I'll give it a test if it doesn't make too much noise and doesn't make too much of a washing machine effect then I'll use it.

 

[waterdrop]

Wow, nothing like a turnover number challange to bring the big guys over to the beginner section! seeing as how I'd probably drool over their beautiful tanks, I'd say we have a statement about not being afraid to try high turnover rates! If aaron could just pipe some turnover and dave s. some carbon dioxide into north carolina they'd have me fixed up.

Hey Trop, about that 304... yes there are criticisms about the fluvals (rabbut can probably give details,) but hey, if you've already got it at low cost then why not give it a "workover" (pull out and inspect the seals, replace if necessary, lube them with vasoline, inspect all the other parts and make moves to replace anything broken) and just generally give it high hands-on maintenance. It may turn out to be too loud but you can eventually make that evaluation. You might even need new hoses.

~~waterdrop~~

 

[dthoffsett]

Just thought I'd add my 2 cents.

You get high turnover rates with mbuna tanks too. 8 -10x is the recommended minimum, I've seen over 20x with no problems.

As for Fluval filters, I've heard a lot of bad things, however, I had two of them (204 & 404) running for over 2 years with no problems, I then sold them (and the tanks) and as far as I know they are still running. Personally I prefer them over Eheim though that doesn't make me too popular.