Can You Over-filter?

[Elsha]

While being sucked into buying a second tank at my LFS today (I was only going in to price things up, honest...) I also picked up a cheap hang-on filter, which I've been meaning to get for my 15-gal for a while now. The price was pretty good, too; NZ$20 reduced down from NZ$176. I'm not sure how much that would translate to in the US or UK, but suffice it to say that $20 is the price of a paperback book here.

The trouble, however, is that this is a massive filter - it's called the Aquamaster 400, and it's intended for a 30 to 100 gallon tank, with a claimed flow rate of 400 gallons an hour. Since my rasboras and tetras seemed to be a bit startled by the 200 litre/hour hang-on filter I've put in their tank to cycle, they're definitely going to be stunned by this! My partner reckons he can either set up a barrier that will minimise the flow rate, or fiddle around with the motor and slow it down. (He's a computer engineering student and our flatmate is in electrical engineering. No electrical item is safe.)

My question is, really, is this feasible? Or is this filter just too damn big for the tank? I incline to the latter opinion, especially since our undergravel filter is working just fine, and I'm quite happy to put this new filter away against a tank suited to its size. Hey, it gives me an excuse to get a tank that size. But I'd also love to know if I'm wrong, or if anyone has any ideas on how to adapt it (preferably not involving resistors, capacitators, and experimental electrical set-ups next to my fishtank.)

 

[dave_gray2077]

Hi

Over filtering won’t directly harm the Biological functions that go on it the tank. However due to the water flow a filter that size will create you tank will end up one big whirlpool. But this will affect the fish if they have to constantly fight again such a current.

Best thing to do is purchase a filter that is correctly rated for your 15g tank. It may be possiable to still use the filter if you can DIY an other power head or impellor into it that will have a reduced flow rate but I don’t think it will be worth the effort from my point of view.

I don’t think adding a barrier in the pipeline is a good idea as may high power filters actually require such a flow to keep the motor cool. Im not entirely sure on this point but im sure someone else can correct me if im wrong.

 

[Elsha]

Heh, cool. It can go into storage until such time as I require it - probably sooner, rather than later, now it's sitting there!