Overfiltration?

[Slatewiper]

I have a 75 gallon tank that I setup about two months and is not fully stocked as of yet. I have an Eheim 350 canister filter with a spray bar and it really causes a strong current on the left side of the tank to the point where only the tetras (Rosy and Black Phantom) will swim over there and even they don't do it often. My Cories and Angelfish won't go near it. I can adjust the flow on this filter to a certain extent but don't know if this would be enough. Did I over do it on the filter? Thanks.

 

[Lunar Jetman]

I don't think you have no. I presume you're referring to the the Classic 350 which, according to the Eheim UK website is for aquariums from 120-350l. Rough calculations into US gallons and that's 30-90 gallons. As you have a 75 gallon tank I'd say you're fine on that side of things.

Personally I always try and get as high a flow rate as i can to keep the water moving and prevent dead spots as I try to grow plants. If your tank was mine I'd probably have two filters on it of that spec, if not higher. But that's me

 

[AbbeysDad]

For a long time there's been a myth in the hobby that "you can't filter too much"... and it's just wrong. Some are so obsessed about a little detritus or mulm on the substrate that they add filters or powerheads to remove. Some even switch to coarser filter media (with more filters) to maintain increased flow and longer filter life w/o servicing.

Good filtration is about how well we filter water, not how much [dirty] water we push through a filter every hour.
Some think they have species that live in fast moving rivers in the wild, never realizing that most of the fish we have in the hobby were born and raised in relatively still tanks and ponds.
Imagine how much effort it takes to swim in fast moving water 24/7.
I believe that we want good circulation in a tank, but not raging waters.

I would reduce the flow, or position the spray bar (or fashion a baffle) to reduce the current to make the fish happy.

 

[Byron]

AbbeysDad is spot on. The fish mentioned here are all quiet water fish. Sedate fish like angelfish cruise, rather than swim actively, and they will be stressed fighting currents. The tetra species mentioned also occur in quiet waters. All of these fish also spend half the year during the "wet" season in flooded forest waters, even less current.

I have Eheim canisters on my two largest tanks, a 4-foot 70g and a 4-foot 90g, with similar fish. I position the spray bar along one end wall, and turn the line of holes directly into the wall. You can adjust this to get some good surface disturbance, but it will significantly lessen the force of water going down the wall and then across the length of the tank. The filter intake should always be at the opposite end of the tank to achieve good flow-through.

In my 90g I do have some fish that like more current, so I removed the spray bar and use just the spigot. But I placed this about 5-6 inches in from the end wall, and direct it into the wall, so the current at that end is strongish but again dissipates down the tank. My spotted woodcats and loaches and Diamond Tetras in this tank appreciate this. But in the 70g the quieter fish would not.

 

[NickAu]

I have been running the tank pictured in my sig on 2 sponge filters, tank.

With 5 Bettas and a bunch of shrimp and all those plants I retired the canister filter.

This is the one I use.

Yes thats a 6 foot 100 gallon tank with only 5 female Betta's and about 50 red cherry shrimp in it.

 

[AbbeysDad]

[Warning: soapbox approaching]
AND on the subject of filters, some folks [especially] with canister filters only service them once every two or three months. The water may look clear (out of sight, out of mind), but detritus decomposes inside a filter and pollutes the water column. Some of these filters become nitrate factories.
The best approach is to routine service filters to get the crud out of the system!
[End soapbox]

Tank on,
Mike