How do I create a current in a tank?

[Gambusia]

I would like to create a current in my tank so I can better keep native fish like warpaint shiners and mottled sculpins.

Any advice on how to do this would be appriciated.

I am looking at getting an All Glass 20 or 40 long.

Thanks

 

[Hound]

I assume you mean a constant current? If so pretty much any of the cannister filters can do what you need if you point the output down the length of the tank. If that's not enough current for what you want you can add a powerhead.

 

[schiejr]

Small powerhead with a sponge prefilter. This should be cheapest. A canister filter would provide current also.

 

[Gambusia]

Thanks.

 

[vaheelsfan]

Get an Aquaclear 500, put it on the end of the tank instead of the back, and then get some pvc pipe and customize your intake so it runs under the substrate to the other end of the tank. This way the current will flow from one end of the tank to the other, kind of like in a stream. The only drawback would be that you would probably have to make a custom top since the filter would be on the end instead of the back. The extra length that the water will have to be pulled by the filter will reduce the flow some, but I'm not sure how much since it would be pulled horizontally instead of vertically. Even with this, an AC500 should still produce a rather strong current in a 20 long.

 

[Richer]

You could also modify vaheelsfan's idea using powerheads. Extend the intake of the powerheads under the substrate to the other side of the tank, and cover those with sponges. That would give you a decent enough filter plus lots of flow if you use the right kind of powerheads.

I experimented with it on my 30 gallon (3'x1' surface area), it worked well enough, but my powerheads were not powerful enough, so I ended up scratching out that idea.

Here's a pic of it just before I filled the tank up.

HTH
-Richer

 

[Hound]

All good ideas. Of course if you haven't purchased your tank or filters yet I still say a cannister will probably be your best bet. Just put the intake tube on one side of your tank and the return flow on the other. That should provide decent enough flow in a 20g long.

 

[zin]

if u wana get alot more flow, u could do a closed loop with a high gph and have a nice stream effect, i would def go with the 40L, or try and find a XL tank,

anyway back to the closed loop idea, you could use a high rated gph pump and run a closed loop from one end to the other, you could also do some custome inlet/outlet covers to dispearse the flows alot and move the whole water volume evenly