Refugium flow rate

[sprouseod]

I have a RSR 350 with a Custom Crystal Reef Sump which has a large refugium. I am curious about flow rates though the refugium and it's effect on efficiency of the fug. I have a slightly over sized pump for the system. This is a Reef Octopus Varios 4 which has a max flow rate of 1050 gph. The 350 is rated for 790. Currently the pump is set to the max output. My question is should I reduce the flow rate to increase the contact time in the fug, or does it matter?

Thanks
Richard

 

[Pntbll687]

I only run chaeto, but the flow through my sump is about 10xdisplay per hour, about 2000g/hr

 

[mcarroll]

My question is should I reduce the flow rate to increase the contact time in the fug, or does it matter?

In a closed system like a tank that doesn't matter in most cases.

In an RODI filter (for example) there's only one chance for the filters to do their work, so it's a 1-pass system. That's why flow rate is so crucial to monitor in an RODI system.

 

[drtrash]

Your pump isnot oversized, if anything its small, minus headloss your in 500-600gph range

 

[Mark Gray]

I run mine at least with a 10 times turn over rate through the fuge. On my new 90 I am pumping 1000 gallons an hour up to the tank according to the flow meters. On the old tank I am guessing but I bet it is a 12 times turn over

 

[drtrash]

Did you mean 1000?

 

[Mark Gray]

Did you mean 1000?

Yes I meant 1000

 

[drtrash]

Worried new trend is no flow

 

[Pntbll687]

Worried new trend is no flow

You could have slower flow through the fuge, say 5-6x tank volume per hour. It may increase contact time, but that may not translate into more nutrients being removed.

Usually if someone has low turnover through the sump, they have high turnover 30+x in the tank using powerheads.

 

[Rakie]

You could have slower flow through the fuge, say 5-6x tank volume per hour. It may increase contact time, but that may not translate into more nutrients being removed.

Usually if someone has low turnover through the sump, they have high turnover 30+x in the tank using powerheads.

Although I fit that criteria I wouldn't say the two are mutually exclusive. I've got about 10-12x tank volume per hour in my sump, and well over 100x turnover in my display. Some people just like slower flow through the sump, as they believe contact time is a big issue.

 

[Randy Holmes-Farley Verified Community Expert]

I don’t think the flow rate through the refugium is very important. IMO, 1x per h (24 x per day) is likely fine. There’s no evidence that high flow is useful, nor any theoretical reason that I have heard to think it is.

Flow in the refugium itself may be more important, but it need not be high.