Is there any recommended SUMP Flow Rate ?

[Carlos Arouche]

In the past, I just read about how fast showd be the Tank to sump flow rate...

By now, there are some people (Sprung, for example) Saying that we should slow down the SUMP flow Rate.

My oppinion is that there is no difference, specially because the skimmer is the key point...

What do you think ?

Best regards.

[mdntrdr]

the slower the flow the better chance the skimmer has to pick up the organics.

[itswayner]

i guess you could always do a recirc skimmer with a direct feed from the overflow and flow as much as you want through the sump?

[Carlos Arouche]

That´s the main question...

Why the skimmer need a low flow rate to take more skimate ?

My (personal and with no scientifc base) oppinion is that there is a constant level of protein in the tank... and Skimmer can take out part of it over the time.

If you slow down the flow, the skimmer will take more protein, but from a small volume of water. If you speed up, will take less protein but from a big volume of water.

And in both cases, if we remember that Aquarium / Sump are a closed loop, the protein skimmer capacity will be exactly the same.

Where I´m wrong ?

Regards.

[itswayner]

good point.

i guess you can look at it as a dilution type problem?

i suppose more important is the contact time INSIDE of the skimmer where the magic happens.

[mdntrdr]

IMO the more times the skimmer misses the organics the better chance of them getting lodged in the system..........detrius.

[Carlos Arouche]

MDNTRDR

I like your point... i think that´s whay there is this new convention to reduce SUMP flow rate.

But IMO the organics will have more chances to lodge in the system if the flow rate is slow and they stay more time in the aquarium....

[mdntrdr]

yea, but you are skimming of the top with overflow and what is then missed gets forced back into the water column.

just my opinion.

[becact]

I did a lot of research on the topic before building my 90 and decided low flow was the best. Too many people look at their return pump as a source of flow in the tank, and it simply is not meant to serve that purpose. Besides the skimmer effectiveness debate, having slower flow gives micro bubbles a chance to escape the water before reaching the return pump, restricts the formation of new micro bubbles from a turbulent sump, is better for a fuge if you have one, and allows detritus to settle out in the sump where it can be removed manually.

Don't confuse display tank flow with sump flow. You can have killer flow in your display to kick up detritus, and still have low flow through the sump. This is only determined by your return pump size.

[kybreos]

I got pretty slow flow through my sump, on my 180, and i have a pretty decent bioload- 3 tangs, 4 anthias, 5 chromis, 2 clowns, 1 tailspot blenny, 1 mandarin, 1 two spot goby plus maybe a couple others that i cant think of now, and my nitrates are 0 and phosphate .03 or less. I dont skim wet but i dont skim dry either, not sure if the slow flow through the sump has anything to do with it but it is a variable.

[Lincutis]

IMHO if organic solids are not being properly handled by the skimming process, should we not consider modification in our skimming process as well as other forms of mechanical removal of said solids. I have observed that larger aquariums have greater mechanical and chemical filtration with greater flow as opposed to concentrating on flow rate to skimmer production. What do you think?

[RogueGrown]

Bump

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[scooter31707]

I usually aim for 3-5x turnover in the sump.

[ca1ore]

In the past, I just read about how fast showd be the Tank to sump flow rate...

By now, there are some people (Sprung, for example) Saying that we should slow down the SUMP flow Rate.

My oppinion is that there is no difference, specially because the skimmer is the key point...

What do you think ?

Best regards.

I think there are enough opinions that you can find one to agree with :lol:

I don't believe there is ANY relationship between sump flow through and skimmer processing .... though, again, you'll find lots of folks who think there is. Just ask them to 'explain' their logic .... and be prepared for an 'onslaught' of bad science.

Single pass skimmers have high through flow; recirculating skimmers have low through flow. I've used both, extensively, and have seen no performance differences based just of flow. Contact time is important, so all things equal, taller is better than shorter.

I go for less turnover (3x nominally from a PW200 feeding 450 gallons of display.) because I've yet to hear a compelling reason for higher. Just burns more electricity.

[DasCamel]

I agree, don't overkill sump flow unless you have a good reason. I'm getting about 4x to 5x in the 375g. Going to probably lower it a tad to around 1200 gph when the skimmer gets installed next week.

[GimpyFin]

I think there are enough opinions that you can find one to agree with :lol:

I don't believe there is ANY relationship between sump flow through and skimmer processing .... though, again, you'll find lots of folks who think there is. Just ask them to 'explain' their logic .... and be prepared for an 'onslaught' of bad science.

Single pass skimmers have high through flow; recirculating skimmers have low through flow. I've used both, extensively, and have seen no performance differences based just of flow. Contact time is important, so all things equal, taller is better than shorter.

I go for less turnover (3x nominally from a PW200 feeding 450 gallons of display.) because I've yet to hear a compelling reason for higher. Just burns more electricity.


I agree with Simon, especially with the part in bold. (Hit the nail on the head, IMO.) I think I'm around 4x flow through the sump on my return.

[75mixedreef]

What about water temp when the heater is in the sump? When it gets cold and people turn down the heat for the night, would there be a significant swing in the display tank temp with a lower flow rate through the sump?

[scooter31707]

What about water temp when the heater is in the sump? When it gets cold and people turn down the heat for the night, would there be a significant swing in the display tank temp with a lower flow rate through the sump?

I haven't any issues with temp changing. Temp is the same with DT and sump.

[ca1ore]

What about water temp when the heater is in the sump? When it gets cold and people turn down the heat for the night, would there be a significant swing in the display tank temp with a lower flow rate through the sump?

Not at 3-5X flow. There are only really two things that would determine 'adequate' turnover. One is heating, as you note; the other is effecting adequate surface skimming of the display. Once you accomplish those two things, any additional flow seems unnecessary.

[Boom215]

Bump

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did you "bump" an over 6 year old post? lol

[RogueGrown]

did you "bump" an over 6 year old post? lol
Yes yes I did... I am wanting to learn about flow rates as I'm going to be starting a sump build.

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[RogueGrown]

I have a 20 gallon tank at the moment. I'd like to take another 20 long and make a sump out of it. Would it make sense to do this? My reasoning is cause when I change my DT to a 40 I'll already have an addiquate sump. Sounds to me like the only thing I'd have to upgrade would be the pump size correct? I'm going to want about 3x flow through the sump.

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[Kevin Guthrie]

A recommended flow rate for your sump, not for your tank, how does it make sense?

Say I have a 10 gallon sump, at 3X I need a 30gph return pump. Say I have the same tank and go to a 150 gallon stock tank for a sump. Now I need 450 gph? That's not right. What am I missing?

Seems to me a larger sump is a good thing, not a bad thing. The gph should depend on the tank size, and the sump should be as big as you have space for.

[RogueGrown]

I thought the flow rate should be of total water volume? If I have 60 gallons between DT and sump I'd need a 180 gph flow rate minimum correct? Or is the flow really just for the sump volume?

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[Mishri]

Sumps are optional pieces of equipment.. flow rate through the sump has no impact on the display tank. The benefits to using one is the surface skimming effect of the overflow and moving equipment out of the display and increasing water volume (dilution).

So some people seem to think contact time with either the refugium or skimmer matters. It doesn't. the refugium will draw nutrients from the water as fast as it can/will no matter how long a particular water molecule is sitting next to it. The skimmer pumps determine contact time, in and through the skimmer, not the flow rate in the sump...


for your question roguegrown, the bigger the sump the better.. just depends on if you have space for it. get a 100 gallon sump.. you don't need to use aquariums, you can use a rubber tub... -this also ties into why flow rate doesn't matter for your sump.. i have a 60 gallon sump on my 300 gallon aquarium, i'm going to have a much higher flow rate through that than someone with a 20 gallon tank with a 100 gallon sump. yet, the only real difference i'll see from using a smaller sump, is less dilution and less space for equipment.

[RogueGrown]

Sumps are optional pieces of equipment.. flow rate through the sump has no impact on the display tank. The benefits to using one is the surface skimming effect of the overflow and moving equipment out of the display and increasing water volume (dilution).

So some people seem to think contact time with either the refugium or skimmer matters. It doesn't. the refugium will draw nutrients from the water as fast as it can/will no matter how long a particular water molecule is sitting next to it. The skimmer pumps determine contact time, in and through the skimmer, not the flow rate in the sump...


for your question roguegrown, the bigger the sump the better.. just depends on if you have space for it. get a 100 gallon sump.. you don't need to use aquariums, you can use a rubber tub... -this also ties into why flow rate doesn't matter for your sump.. i have a 60 gallon sump on my 300 gallon aquarium, i'm going to have a much higher flow rate through that than someone with a 20 gallon tank with a 100 gallon sump. yet, the only real difference i'll see from using a smaller sump, is less dilution and less space for equipment.
This answers alot of ?s for me thank you!!!!

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[Starvin Marvin]

I would also guess that unless you have specifically measured the flow rate of your return pump, it's probably producing much less flow than you thought.

For example, on my 110 gal system, my return pump is a 'Jebao / Jecod DCS 12000 Silent Pump (2375 to 3170 GPH)' which according to the Curve chart says I should be able to get a maximum of 3170 GPH at 0 ft, and 264 GPH at 14.8 ft.

With the vertical distance from the top of the water in the return pump chamber of the sump, to the top of the elbow of the return plumbing in the display tank, being only 43.5", the Curve chart indicates that I should be getting 2470 GPH.

The DC pump has a low-high adjustment range of 75% - 100% of the curve.

I'm running mine on the lowest setting which means I should be getting 2470 * 75% = 1853 GPH.

In reality however, when I connect a large hose to the output and divert the water into a 5 gallon bucket, it took 46 seconds to fill it up to 4.16 US gallons.

So that equates to a mere 325 GPH of actual flow.

During the 46 seconds, the water in the return chamber of the sump gradually lowered until the pump was just about to start sucking air since that's how much water that chamber holds and hence why I stopped the test before I got closer to 5 gallons.

So as the eater dropped by approx 7" in that chamber, the head pressure to overcome would have been increasing in a linear fashion throughout the whole 46 second test.

I figure that it would have slowed down approx 11% over that period which means that the actual flow rate could be slightly higher than 325. Perhaps 340, I'm not sure how to actually create or solve the proper function to calculate that.

But I think 340 GPH is an accurate enough number.

It's way lower than I anticipated when I was "designing" my components but after realizing it was so low, I also did a lot of reading and realized as well that it's 3.1x my total system volume of changeover per hour.

Which is absolutely PERFECT for me.

If you haven't done a similar test, you might be surprised at what you find your actual return pump flow rate is.

And that might be proof enough that you are happy with it the way it is.


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[Fish finder]

I have a skimmer that is rated to skim 425 gph, so that is roughly what I will shoot to flow through my sump

[ca1ore]

I would also guess that unless you have specifically measured the flow rate of your return pump, it's probably producing much less flow than you thought.

Certainly possible, maybe even likely, though the degree to which probably depends on the 'credibility' of your pump. I've done the bucket test (soon the FFM) on my PW 200, and the calculated flow is very close to the actual flow (1,400 gph or thereabouts). Not really surprised that the Jebao pumps underperform :)

[ca1ore]

I have a skimmer that is rated to skim 425 gph, so that is roughly what I will shoot to flow through my sump

I see this kind of thing posted all the time and cannot figure out why people seem to get stuck on matching sump through flow with skimmer pump capacity. Care to share your reasoning?

[Starvin Marvin]

Not really surprised that the Jebao pumps underperform :)


No doubt! I also have noticed that my "spare" pump which I use to pump salt water from garbage bins to my tank upstairs, has decreased in performance over a short period of time, as if the impeller clearance or canes have changed/worn.


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[Fish finder]

I see this kind of thing posted all the time and cannot figure out why people seem to get stuck on matching sump through flow with skimmer pump capacity. Care to share your reasoning?

I'm very new to this so hopefully you can help me out.... but I don't see the need to run the water through my skimmer multiple times before it goes back to the tank.

If I flow 100gph through the sump and my skimmer does 400gph that means it'll skim most of the water 4 times before returning. Seems redundant. But I'm very new, please correct me if I'm wrong.

[ca1ore]

I'm very new to this so hopefully you can help me out.... but I don't see the need to run the water through my skimmer multiple times before it goes back to the tank.

If I flow 100gph through the sump and my skimmer does 400gph that means it'll skim most of the water 4 times before returning. Seems redundant. But I'm very new, please correct me if I'm wrong.

I was merely curious. The reality is that even if you match sump flow through with your skimmer not all of the water will 'magically' go through the skimmer. Some will go right past and some will go through more than once. One could build a sump so that most would go through the skimmer (in fact I did that once), but it's unnecessary because a skimmer does not remove all the organics it can in just a single pass. Otherwise recirculating skimmers wouldn't work.

[Fish finder]

ok i gotcha, that makes sense