Sump/Skimmer Flow rates: Match?

[jbdreefs]

Good morning all,

I recently picked up my "new" tank, and I'm just brainstorming about how it should be setup. I started to think about the sump, when I remembered reading about flow rates through the sump. Can there be too much flow through a sump?

I've read that matching the flow rate through the sump with the actual flow rate through the skimmer maximizes the skimmers efficiency. However, I can certainly present an argument to the contrary. I guess this theory suggests that the flow rate through the sump should only be the water volume processed by the skimmer. Therefore, the water returning to the tank would have theoretically been processed by the skimmer.

However, we all know (or can atleast understand) that an in-sump skimmer will not process 100% of the water flowing through the sump, even if the flow rates between the sump and skimmer are identical. When using an in-sump skimmer, water will find a way to by-pass the skimmer intake and flow directly to the return pump.

The only way that I can see achieving the goal of processing 100% of the flow through the sump would be to plumb an external skimmer in-line with the drain.

In theory, this setup avoids returning DOC's to the display tank. Is it that big of a deal?

Let's look at my future tank as an example:

180 gallon tank
48x18x12 operating sump volume (45 gallons)

In order to turn my tank over 5 times per hour, I need to pump 900 gallons of water into the tank. Accordingly, 900 gallons of water will flow through the sump per hour. The turn over rate for the sump would be 20x per hour! That sounds insane to me!

Is it even possible to process 900 gallons of water with a non-commercial skimmer? The pump on the Octopus NWB200 is rated for 750 gallons per hour. I've read, however, that venturi/needle wheel pumps do not actually pull the "rated" amount of water into the skimmer because they also pull in air.

Maybe I'm over thinking this process too much and making a bigger deal out of it than needed, but I'd be interested in hearing your thoughts.

 

[grouper therapy]

As long as the DOCs stay suspended it make s no difference since it is one unit/ body of water. Think of it this way, if too much water passing by the skimmer in a given time period effected it's efficiency, then the same skimmer placed in the display tank would be rendered useless. There are other types of filtration that could be effected but not the skimmer if the flow to it is consistent.

 

[ichthyoid]

Having a pipe with water coming out, at the surface of the sump pointing down toward the skimmer intake, will do more than any calculation.

Much of the stuff you want to skim is lipophilic (fat loving/oily). By squirting it down toward the intake much more of it gets removed.
-JMHO

FWIW- I think you can have too much flow through a sump. As for refugiums, there is no doubt.

 

[grouper therapy]

Exactly the skimmer is only gonna process the amount you feed it via it's own pump (non recirculating) or via an external source ve.overflow directly in or a another feed pump The more organics you either pump into it( with in it's limits) or present to it at the intake of it's own pump the better the odds of it getting it removed

 

[jbdreefs]

grouper therapy;800913 wrote: As long as the DOCs stay suspended it make s no difference since it is one unit/ body of water. <span style="color: red">Think of it this way, if too much water passing by the skimmer in a given time period effected it's efficiency, then the same skimmer placed in the display tank would be rendered useless.</span> There are other types of filtration that could be effected but not the skimmer if the flow to it is consistent.

Excellent point.

 

[jbdreefs]

I'm planning to force water flow in the sump through some matrix. Do you think that 900 gallons/hr is too fast to reap any benefits? There are a couple ways that I can slow down the flow through the matrix if needed.