Return Pump Flow Rate Opinions?

[ca1ore]

The problem is, everyone is of the opinion that they are removing dirty water and returning clean water, and that's not entirely correct. If you're flow could be low enough to see a major difference between your overflow and return water, once the "clean" water enters the DT with all the powerheads/wavemakers, it gets mixed. So regardless of flow, once your system is running, it strikes a balance.

Don't know that 'everyone' is of that opinion, but it certainly is prevalent. The vagaries of fluid dynamics are such that some water passing through a sump is never processed before returning to the display, other water is processed many times; so the notion of dirty in/clean out is really rather silly ..... as you note. It is also patently untrue that a typical skimmer removes all removable proteins in just a single pass. Easy enough to setup an experiment (which I have done) to easily prove this. The reality is that even water that has been processed retains wastes. So water returning to the display may be cleaner than that which drained down, but it is not completely clean.

 

[WWIII]

I like 3x to 5x turnover because it's cheaper for me with a basement sump and a 200 gallon tank. On my other tank I have more than 10x turnover because it's on the same level as the sump. Somewhere between 3x and 10x is a good general number imo.

I did just make a new pump purchase, so I will probably be bumping the flow up a bit. The thing is on my 200 dd tank the overflow weirs can only handle so much, then the water level in the tank gets higher. If I had a coast to coast or a large ghost overflow on my main display I may shoot for 5x to 7x.

Also depends a little on sump size. If you have 2k gph flowing through a 30 gallon sump it gets a little sketchy from my experience.

 

[Matthew Frost]

This is faux-logic. It's something that 'seems' like it ought to make sense, and is oft perpetuated in the hobby; but if you take time to think about how a skimmer works, it really makes no sense. Now, you did use the word 'effectively', and that may add some nuance to the argument; but the broad assertion that skimmer and return pump have some kind of synergy is untrue.

I disagree, your equipment in your sump and return pump work together to keep your tank clean and healthy. If your skimmer can only effectively clean/filter "X" amount of water and you are recirculating 4 times "X" you are simply circulating dirty water. You are encouraging evaporation, increasing salt creep and wasting energy. I fail to see how that is faux logic.

 

[ca1ore]

I disagree, your equipment in your sump and return pump work together to keep your tank clean and healthy. If your skimmer can only effectively clean/filter "X" amount of water and you are recirculating 4 times "X" you are simply circulating dirty water. You are encouraging evaporation, increasing salt creep and wasting energy. I fail to see how that is faux logic.

OK, let me ask you this ..... skimmer 'processes' 500 gph so you pick a return pump that nets same. Do you think that in most sumps all of this return water will magically be inhaled by the skimmer? I'd suggest that unless you very carefully design the sump, a percentage of the 500 gallons that is drained from the tank will bypass the skimmer and be returned to the display 'dirty'. I'd argue that the vast majority of sumps are not designed to avoid this problem, thus invalidating the matching argument. Second question ..... do you think that passing 500 gph though a small plastic cylinder with a bunch of air bubbles will remove all the removable organics in just a single pass? I'd suggest that the answer is resoundingly no (otherwise recirculating skimmers would be pointless). Further invalidates the matching argument. I do agree that higher levels of turnover are a waste of energy, and largely unnecessary, though I fail to see why this affects evaporation in any material way.

 

[Matthew Frost]

OK, let me ask you this ..... skimmer 'processes' 500 gph so you pick a return pump that nets same. Do you think that in most sumps all of this return water will magically be inhaled by the skimmer? I'd suggest that unless you very carefully design the sump, a percentage of the 500 gallons that is drained from the tank will bypass the skimmer and be returned to the display 'dirty'. I'd argue that the vast majority of sumps are not designed to avoid this problem, thus invalidating the matching argument. Second question ..... do you think that passing 500 gph though a small plastic cylinder with a bunch of air bubbles will remove all the removable organics in just a single pass? I'd suggest that the answer is resoundingly no (otherwise recirculating skimmers would be pointless). Further invalidates the matching argument. I do agree that higher levels of turnover are a waste of energy, and largely unnecessary, though I fail to see why this affects evaporation in any material way.

You're stuck on one aspect and not looking at the bigger picture. The argument is "what return pump should I purchase in order to capture a turnover rate of X". That's the wrong way to look at it. The question should be, "what is my filtration system capable of effectively filtering and the equipment in that filter capable of reasonably processing? No, every ounce of water does not go through the skimmer and no every molecule of "waste" is not removed when it passes through the skimmer. But if we look at what each piece of equipment is capable of doing and design closer to those numbers rather than I need to have a turnover of "X times per hour" I think the whole system functions better and more efficiently. As far as evaporation is concerned, the more surface agitation you have both in the sump and in the DT the more evaporation you will have.

 

[mta_morrow]

I run the Jebao DCS6000 on my RSR525XL, 108 gallon display, 33 gallon sump. I run it at 75% and it is dead silent. It really all depends what you are trying to accomplish.

For me, all I HAVE to do is run enough water over my heater. I am probably around 5-6X turnover per hour.

 

[Dimmy007]

Does anyone know on this model the Jebao DCQ-5000 what the numbers on the controller mean. The instructions just say adjust the flow rate with the + & - buttons. It does not say what the numbers mean. The way I adjusted my flow is so the water level in the return compartment is a couple inches below the Skimmer compartment. That way it seems that all the water coming in is at a constant flow coming in then going through the skimmer then into the return compartment. Maybe I'm wrong doing it this way. Obviously if I reduce the flow rate the return compartment becomes to high and then the water coming from the skimmer does not flow over.

 

[theMeat]

4-6 times for 75gal or less
3-5 times for bigger tanks

 

[mta_morrow]

4-6 times for 75gal or less
3-5 times for bigger tanks

That’s all you need! Agreed!

 

[WWIII]

Does anyone know on this model the Jebao DCQ-5000 what the numbers on the controller mean. The instructions just say adjust the flow rate with the + & - buttons. It does not say what the numbers mean. The way I adjusted my flow is so the water level in the return compartment is a couple inches below the Skimmer compartment. That way it seems that all the water coming in is at a constant flow coming in then going through the skimmer then into the return compartment. Maybe I'm wrong doing it this way. Obviously if I reduce the flow rate the return compartment becomes to high and then the water coming from the skimmer does not flow over.

It's probably displaying the wattage.

 

[Coral Passion]

Go with the flow and choose what ever makes you happy. IMO the only reason you would need to worry about flow rates are for sterilization reasons and if you have no other flow in your tank.

 

[ca1ore]

You're stuck on one aspect and not looking at the bigger picture. The argument is "what return pump should I purchase in order to capture a turnover rate of X". That's the wrong way to look at it. The question should be, "what is my filtration system capable of effectively filtering and the equipment in that filter capable of reasonably processing? No, every ounce of water does not go through the skimmer and no every molecule of "waste" is not removed when it passes through the skimmer. But if we look at what each piece of equipment is capable of doing and design closer to those numbers rather than I need to have a turnover of "X times per hour" I think the whole system functions better and more efficiently. As far as evaporation is concerned, the more surface agitation you have both in the sump and in the DT the more evaporation you will have.

..... always looking at the bigger picture. I'd actually argue that the proper turnover has almost nothing to do with aspiring to a particular X, and not much more to do with filtration in the sump (heck, most waste processing takes place in the display anyhow for all you ''bigger picture' people). I wrote a piece almost a decade ago on RC arguing that display turnover really was about just two things: enabling proper temperature transfer between the sump and the display and effecting adequate surface skimming in the display. Everything else either marginal or imagined. Probably nobody remembers because the median time in the hobby is a few years LOL.

 

[rockskimmerflow]

..... always looking at the bigger picture. I'd actually argue that the proper turnover has almost nothing to do with aspiring to a particular X, and not much more to do with filtration in the sump (heck, most waste processing takes place in the display anyhow for all you ''bigger picture' people). I wrote a piece almost a decade ago on RC arguing that display turnover really was about just two things: enabling proper temperature transfer between the sump and the display and effecting adequate surface skimming in the display. Everything else either marginal or imagined. Probably nobody remembers because the median time in the hobby is a few years LOL.

Yup nailed it. I run some converted to reef client tanks with no sump and just powerheads for flow. So long as I have an in-tank surface skimmer and adequate temp control in the room, there really seem to be few advantages to a sump system other than the aesthetics of hiding most equipment.

 

[dimidragos]

Hello, I don’t know soo much about the best flow but I ca speak about flow with Jebao Dsc 5000. I have an 129g DT and 25g sump , I use 32mm pipes between the sump and tank. The tank it’s 1.5 meter high and I get real flow with pump in full throttle max 2000 liter per hour. The pipeline contains two short 90 elbows and one long 90 elbow. I check also the consumption of the pump an it’s 76w at full throttle. The manufacturer power usage it’s 40w. Honestly I’m pretty happy with that flow and I believe it’s a 4x flow. I’m not happy to use so much extra electricity and a big plump to move that amount of water. I all ready order the Sicce SDC 7 WiFi and I really hope not have a bigger flow but a better rate.

 

[dimidragos]

Regarding what I have written in my previous post you speak about the flow written on the pump or the real flow in the tank??

 

[Retro Reefer]

I think the old 10x per hour is outdated.. I shoot for around 5-7 times per hour, the new DC pumps make dialing in flow a breeze

 

[GoldeneyeRet]

I'm in the camp that one only needs enough flow for effective surface skimming and heat control, any more than that is superfluous.

4 to 5 times display volume works for me.

 

[ca1ore]

Regarding what I have written in my previous post you speak about the flow written on the pump or the real flow in the tank??

They're completely different. I run 1,200 GPH nominally through my sump on 400 display gallons, but many thousands within the tank with various propeller pumps (two MP60, three WAV and even a Jebao) and a closed loop. I even looked at a hydrowizard before concluding it was an absurd amount to spend on a powerhead. Though I suppose absurd is a relative term in this hobby LOL

 

[ca1ore]

I'm in the camp that one only needs enough flow for effective surface skimming and heat control, any more than that is superfluous.

4 to 5 times display volume works for me.

Ironically the biggest challenge I have is maintaining enough return flow through my chiller so that it doesn't short cycle. Really should have bought a smaller one ..... oh well.

 

[sghera64]

I have been reading many different opinions on what the flow should be. I'm sure there will be many opinions here as well. So what is everyone's opinion on what the flow rate should be for the return pump.

I have 110 gallon tank

- 180 gal system
- wmd-30R Iwaki pushing 750 GPH
- with height and fittings head loss
- 20 gallon sump
- that’s 2.5x turnover and my system is fine