Flow Rate Required For A River Tank

[tenohfive]

I'm planning a 90L river tank at the moment - full details in this thread.
I'm planning to run an Eheim external and a Fluval 2+ for filtration but I'm planning on adding a powerhead as well to put out alot of flow.

In a tank with danio's, possibly rainbows, sewellia lineolata and a handful of corys, how much flow rate do I want the powerhead to be putting out?

 

[nmonks]

Over on the Loaches forum, there's an article on a DIY "river tank manifold" system that uses sponge filters at one end as the inlets, connected to plastic pipes running under the gravel, and then up into powerheads that pull the water through. The end result is a strong flow of water, rather than mere turbulence. It's pretty neat, and I've seen these tanks in action, and they do work well.

Failing that, anything from ten times the volume of the tank upwards in turnover per hour will suit Sewellia, Gastromyzon and the like. Barilius and other hillstream cyprinids would do well with that too. That's actually going to be a little on the steep side for danios which, despite their reputation, don't actually come from turbulent streams. Unless you're keeping hillstream fish, 8-10 times the volume of the tank in turnover per hour is fine for danios, minnows, rainbows, Corydoras, etc.

Cheers, Neale

 

[tenohfive]

Cheers, I'll have a nosy over that way then. If push comes to shove 9-10 times turnover seems like a reasonable compromise, though if one or other aren't happy in those conditions I can reassess and rehome as required.

 

[hollanda88]

Cheers, I'll have a nosy over that way then. If push comes to shove 9-10 times turnover seems like a reasonable compromise, though if one or other aren't happy in those conditions I can reassess and rehome as required.

I have got 18X turnover on a 90L tank with angels whih is fine for them, so it depends a lot on how the flow is distributed.

 

[tenohfive]

Cheers, I'll have a nosy over that way then. If push comes to shove 9-10 times turnover seems like a reasonable compromise, though if one or other aren't happy in those conditions I can reassess and rehome as required.

I have got 18X turnover on a 90L tank with angels whih is fine for them, so it depends a lot on how the flow is distributed.

I'm quite keen to have high flow as opposed to high tank turnover. I'm not planning on dividing it up with spray bars - I want that powerful flow effect, I want it to be an active tank and to look active - and more importantly/as importantly to be a suitable environment for sewellia lineolata.

Neale, I've just realised the site doesn't have a loaches forum (thought it was odd I'd not heard of it.) Any chance you can point me in the direction of the link you were talking about?

 

[tenohfive]

I think I found the article about river tank manifold systems:

http/www.loaches.com/articles/river-tank-manifold-design

Seems like a good idea, though I'm reconsidering the overall design. My concern is that with the manifold system, in order to get sufficient flow you need quite thick piping. In a 90L long (3ft x 1ft x 1ft) tank, hiding the piping in the substrate may be an issue. On the bright side, an Eheim Compact 1000 (variable flow from 150 l/h to 1000 l/h) seems quite cost effective and not too big.

I might pop to the garden centre to see if I can get hold of some suitable rocks and slates that would enable me to divert the flow, so that the flow runs down the middle of the tank (with smooth rocks etc for the S. Lineolata) then using rocks and slates gets diverted back round one side of the tank, with alot of the flow being taken out by the placement of rocks etc and as such making a suitable area for corys. Danio's I can live without, cory's I'm less keen to. Will have a think, if a suitable compromise isn't an option I'll have to pick one option or other. My biggest concern with going for a river tank manifold design is that apart from hillstream loaches I don't know of many other fish that would be happy in such conditions.

 

[tenohfive]

I might pop to the garden centre to see if I can get hold of some suitable rocks and slates that would enable me to divert the flow, so that the flow runs down the middle of the tank (with smooth rocks etc for the S. Lineolata) then using rocks and slates gets diverted back round one side of the tank, with alot of the flow being taken out by the placement of rocks etc and as such making a suitable area for corys. Danio's I can live without, cory's I'm less keen to. Will have a think, if a suitable compromise isn't an option I'll have to pick one option or other. My biggest concern with going for a river tank manifold design is that apart from hillstream loaches I don't know of many other fish that would be happy in such conditions.

Bump, any thoughts on the above?

 

[nmonks]

That is kind of the point... hillstream loaches, botiine loaches, nemacheline loaches, barilius, minnows, Garra, etc. all come from a very specific habitat different to that of standard rainforest or lake fishes. Temperature is a bit of an issue, excluding things like Steatocranus spp. cichlids. But if you don't mind stretching a point, the cool water Scleromystax spp. would make ideal additions to a hillstream system.

Cheers, Neale

My biggest concern with going for a river tank manifold design is that apart from hillstream loaches I don't know of many other fish that would be happy in such conditions.

 

[tenohfive]

The temperature isn't a huge issue - if I were to settle on 22 degrees (within loaches.com recommended range for s.lineolata and SF range for danio's and corys) things could work.

Another option would be to setup a spare 65L purely for S. Lineolata. 650 l/h would be achievable provided I got the tank layout right and if I stuck with a small group (4 maybe) there shouldn't be any issues.

Assuming I stayed true to the 90L idea, what do you think of the idea of using rocks and big flat pieces of slate dividing the 90L top to bottom? Powerhead pushing out current in the top half, bottom half sheltered for the cory's etc. Leaving a slim area at the front thats open all the way up though, like illustrated below:

Apologies for the bad artwork but you get the idea. If I ran the powerhead intake below the slate dividers (and the external intlet) could this work?

Probably not a great idea for danios, but for S.Lineolata and corys maybe...?
Might be a really bad idea, I'm just trying to work out what my options are. I'm not rushing into anything, I'm a firm believer in proper planning.

 

[tenohfive]

Bump...struggling for answers as to whether the above would work. Have posted on loaches.com, but still no answer there either.

Rather than something that would run the length of the tank I've found some 2ft x 1ft x 1ft piece of slate at the local gardening centre, which could be ideal if the idea is workable.

Any thoughts from those who know about S.Lineolata?

 

[nmonks]

I wouldn't worry too much if creating a manifold design is outside your range of skills! Provided the aquarium had good turnover, you'd get just as viable results using an external canister filter that had the inlet at one end of the tank and the outlet at the other.

Alternatively, two internal canister filters, one at each end, one pushing water along the back pane of glass and the other along the left or right panes of glass, would also create a filter with nice, even flow.

You could even use an undergravel filter, provided there were two or more strong powerheads that really shifted the water about.

The major reasons people fail with Sewellia are feeding, temperature and oxygenation. How you solve those problems is entirely up to you; the river manifold design merely happens to be one particularly elegant solution.

Cheers, Neale