Flow in FOWLR Tank?

[Kasey Grohowski]

I read that 20x turnover is minimum in a fowlr tank, which I have (5300 gph on full blast in a 220), but I was wondering if I should turn it to minimum (450 gph) before bed to let the fish rest? Any suggestions?

 

[James M]

Turn it to minimum but you shouldn’t turn it down every night.
The ocean doesn’t turn down its flow to allow fish to rest

 

[Kasey Grohowski]

Turn it to minimum but you shouldn’t turn it down every night.
The ocean doesn’t turn down its flow to allow fish to rest

Every other then or?

 

[mort]

20 times turnover is nothing to fish. In many sps reef tanks people have 50-60 times turnover or even more. With higher turnovers you see healthy fish as they exercise and as long as they have sheltered areas where they can rest I wouldn't worry about it at all.

 

[Kasey Grohowski]

20 times turnover is nothing to fish. In many sps reef tanks people have 50-60 times turnover or even more. With higher turnovers you see healthy fish as they exercise and as long as they have sheltered areas where they can rest I wouldn't worry about it at all.

Sps tanks need that high flow.

 

[sde1500]

Sps tanks need that high flow.

His point is that the fish are fine with flow that high, so 20x in your tank is fine as well.

 

[mort]

Sps tanks need that high flow.

As above, I simply meant that 20x turnover may sound a lot but it isn't anything compared to the currents fish natural live in. The fattest healthiest fish I've seen have lived in tanks where the current is really strong.

Have a look at this video for an example of strong current from a well respected experts tank https://reefbuilders.com/2015/03/06/intimate-video-fish-tank/

 

[Kasey Grohowski]

As above, I simply meant that 20x turnover may sound a lot but it isn't anything compared to the currents fish natural live in. The fattest healthiest fish I've seen have lived in tanks where the current is really strong.

Have a look at this video for an example of strong current from a well respected experts tank https://reefbuilders.com/2015/03/06/intimate-video-fish-tank/

Wow that's insane.

 

[Kasey Grohowski]

Does anyone know if elasmobranches like higher flow as well?

 

[mort]

Does anyone know if elasmobranches like higher flow as well?

Depends on the species. I guess your thinking cat or bamboo sharks rather than a black tip and the answer is yes, some sharks need constant water movement over the gills or they can drown (this is why they never stop swimming). The more sedentary species don't need massively strong currents but they do like water movement.
It's not so much the turnover that's beneficial but the way you use the flow. In that vid the flow is built up by the gyre mass movement of water but if you had the same amount of flow but split into equal flow from two different directions, the flow wouldn't be as strong.

So my advice is to not get to hung up on the amount you need. It's a simply thing to fix in the future if you see the need (like detritus collecting in deadspots) but it depends on how you aquascape, how much flow through the sump etc. So I'd start with your 20x and go from there if you think you need to.