The SUMP SLOW DOWN: The benefits of slowing down the water?

[ShawnSaucier]

It’s funny that this popped up. I just replumbed my system to add more flow to the sump. I have three holes in my overflow: return, drain and emergency drain. Now it’s a full bean animal with the return coming up over the back of the tank. It’s only been completed for just over a week. I’ve got about 30% more flow going through the sump at this point. My skimmer filled up a bit quicker this past week since the change, but a bit wetter than I normally like. PH bumped up a small amount also. I think due to more turbulence in the “crash” compartment of the sump. Only 0.3 difference. We will see how much difference it makes in the long run.
I would suggest trying it, what could it hurt?

 

[Javamahn]

I voted other because I do not think there is one right answer. Every point that is part of the filtration has an optimum setting for efficiency and setting the flow through the entire system does not guarantee that all points are at that setting. The contact time in a skimmer is based on the size of the pump in that skimmer not flow through the sump. I think the best we can do is set and tune each filtration piece based on results and then allow the system to equalize to a negative or positive result. That process takes time and patience.

 

[Reefs and Geeks]

My last sump/return pump/drain setup I was only able to get 2X turnover in my tank and was still able to maintain a low nutrient system. I've since upgraded to a sump that is the same size as my display, and about 15X turnover. With the large sump, the turnover of the sump (not the display) is still similar, which may matter. I do keep a couple of powerheads in the sump to keep detritus kicked up and when I was running a fuge to help keep fresh water from the display in contact with the cheato and deep into the cheato. I did notice some slight improvement in algae when I switched, but nothing too exciting. I keep my turnover about as high as I can now simply to get free floating stuff out of the display and into my socks.

 

[Conrad]

I believe in slower flow if you have a refugium. I think it should be less than 10x turn over rate per hour. But don't believe in going super slow like a few times turn over rate as you aren't turning over the system enough. I have about 8x an hour and have a power head in my 75G sump to keep stuff from settling. Everything will work, I think its just tuning to your system and needs. I also have my sump filled with rock and don't run a refugium as I use a scrubber and skimmer but do run a light over the sump still.

 

[K7BMG]

IMO - this is not a valid theory in the case of recirculated aquariums - in your example it is always new raindrops coming in - in an recirculated aquaria - its the same raindrops that hit you - over and over again - and if they will stuck - they are not coming back.

Sincerely Lasse

Yes I get your point, but I was refrencing flow in general.
I maybe should have said if I was sitting in a closed room.
Me being the Algae.
How many air molecules am I in contact with?
Say theres 10 billion overall in the room, and I am personally in contact with only 5 thousand under a no flow situation. All I will ever touch is the 5 thousand.
Then I add a computer fan and start blowing air on me, now I have doubled my contact with the air molecules in the room to 10 thousand now, and the particals in the room are now moving around instead of stagnant. So yes I would be getting hit with some of the same ones now.
Then I swapp the computer fan out for a fan on a stand and now I the algae is getting hit with 100,000 molecules. Up the fan size again and up the amount of molecules by X amount.

The point is weather they are the same particles in the closed room vs new if I were sitting in a wind tunnel the volume of contact to air molecules overall would be greater with the more flow.

I agree there will be a sweet spot for every tank out there. Thats the real fact of the matter.

Way to many variables to say that low flow is better than high or vice versa.

Fuge lighting alone will make a huge differance.
The amount of time the lighting is on or off.
Water chemistry.
Amount of nutrients.
Livestock.
Type of algae used or combination thereof.
Temprature.
Dosed additives.

So yes everyone here who wants to stand on this flow is better.
They are exactly right, but for their tank.
Because the next guys sweet spot will be entirely and dramatically different.

 

[Grant Beyleveld]

Yes I get your point, but I was refrencing flow in general.
I maybe should have said if I was sitting in a closed room.
Me being the Algae.
How many air molecules am I in contact with?
Say theres 10 billion overall in the room, and I am personally in contact with only 5 thousand under a no flow situation. All I will ever touch is the 5 thousand.
Then I add a computer fan and start blowing air on me, now I have doubled my contact with the air molecules in the room to 10 thousand now, and the particals in the room are now moving around instead of stagnant. So yes I would be getting hit with some of the same ones now.
Then I swapp the computer fan out for a fan on a stand and now I the algae is getting hit with 100,000 molecules. Up the fan size again and up the amount of molecules by X amount.

The point is whether they are the same particles in the closed room vs new if I were sitting in a wind tunnel the volume of contact to air molecules overall would be greater with the more flow.

Sorry @K7BMG but I'm going to have to respectfully disagree. Your interpretation ignores that native capacity of the algae to remove nutrients, and assumes that if it sees more nutrients it will uptake more nutrients, which I'm sure is not the case.

Sticking with the hypothetical - you're the algae - you can only take up nutrients at a certain rate. If I pump more and more past you, you're still only going to uptake at a certain rate. Switching metaphors, imagine you're at an all-you-can-eat sushi buffet - the kind where there's a conveyor belt of dishes coming past you. You can only eat so much sushi per hour. I'm sure your role in this metaphor is clear!

Assuming you sit there all day, if the belt is way too slow you'll eat everything that comes past and always be hungry, never satiated. This is obviously not ideal.

Now if the flow is too fast, you won't suddenly eat more sushi than your body is capable of. Instead, you'll satiate yourself and then the excess sushi will simply keep going around and around until you're ready to take it up.

The former is undesirable - the system could absorb more nutrients but their arrival is too slow. The latter is great! You get all the sushi you want, when you want.

In this setup, more flow is better. But beyond a certain threshold the filter is maximized and anything more is extraneous. It may be beneficial in other ways, such as increased oxygen levels, or keeping flow in your DT high enough for your corals, or causing your chaeto to tumble, or whatever you need it for.

I think this is the crux of the question: you want enough flow that your filter (whatever that may be - macroalgae, biopure, skimmer, etc.) is running at its max capacity, and then anything after that might have benefits or disadvantages based on your system.

It's also worth pointing out that maximizing the efficiency of your filter might also be undesirable. You might not want to remove that many nutrients from your tank. In which case, having a flow rate that has the filtration system starved (i.e. not maximized) might be exactly what you want. Or you need higher flow for other reasons, so you downsize the filter (prune the chaeto, turn the fuge lights down, put the skimmer on a timer or dial the skimmer pump down, etc. etc.).

Going back to the sushi metaphor, the goal here is a certain amount of sushi on the conveyor belt. If there are plenty of hungry customers sitting in the restaurant but you're sending sushi past them too slowly, the kitchen (the DT) is going to get backed up and there will be too much sushi hanging around.

Alternately, if there are too many customers, they'll eat all the sushi and maybe they'll be hungry all the time no matter how fast you dial up the conveyor.

Ultimately, the cleanliness of the water (the average amount of sushi on the belt) needs to be balanced with the size and efficiency of the filter (how many customers are in the restaurant).

Sorry, I think this metaphor went too far. Haha

 

[Mike N]

I like metaphors.

 

[K7BMG]

Ha ha ha.
Yes I agree with you on all accounts.

You do realize that you 100% backed up my context.

You may have done it more eloquently than I have but in fact we are saying exactly the same thing.

My metaphore(s) were singularly linear in regard to flow only. The speed of your Sushi belt alone.
Other interpretations, situations, and occurance is was not meant to be added or implied.

 

[sarcophytonIndy]

Unless there is some specific organism that you are trying to cultivate that requires low flow, I see no point. The triton method recommends at least 10X. And I have no nuisance algae in the display. Couldn't be happier

 

[Grant Beyleveld]

Ha ha ha.
Yes I agree with you on all accounts.

You do realize that you 100% backed up my context.

Look at us engaging in civil internet discourse! Perhaps we should turn our attention to politics or religion since we're so adept

Unless there is some specific organism that you are trying to cultivate that requires low flow, I see no point. The triton method recommends at least 10X. And I have no nuisance algae in the display. Couldn't be happier

I sort-of agree with this. I think for most people, the turnover through the sump isn't their main source of flow in the DT in any case (although I stand to be corrected on this), so speed-up or slow-down through the sump won't impact overall flow, give the power heads are really doing the heavy lifting in the DT.

But yes, I think higher than necessary flow through the sump can't hurt, unless you've got a refugium with substrate you don't want to blow around. But I stand by my point that slower flow than we've all been taught is not necessarily a bad thing either, assuming you have other sources of flow in the DT.

(edit: spelling)

 

[Suohhen]

Sump flow rate is a balancing of many factors leaning pretty heavily towards slower flow imo.
Slower flow rates create less noise (albeit high end pumps are able to run silently at high flow rates and proper plumbing can as well), less heat (heat can be a pro or con), use less electricity, and increase the concentration of surface skimmate (high DOC water) entering your sump benefiting the skimmer.
The benefits of higher flow are more aeration (which is often dwarfed by the effect of the skimmer and powerheads anyhow), elimination of dead zones in the sump (which can be more easily and effectively eliminated with powerheads anyhow), allow the heater to maintain DT temperature (only way around this is to put a heater in the DT or Refugium if the Refugium is plumbed directly to the DT), and finally Refugium turnover rate (phosphate is constantly being released into the system via fish grills and the faster that phosphate can reach the Refugium the more likely it is to be taken up by your macroalgae than the algae in the DT). Of course this is balanced by the fact that many corals compete for phosphate as well.
In conclusion the heater and Refugium set the floor of sump turnover and these two vary greatly between systems.

 

[Bruce60]

Outstanding discussion!

I voted that changing the flow rate does not make a difference. Not to repeat too much, a couple of points:

1. A skimmer does not remove 100% of what you want it to remove, and the water coming out of a skimmer is not 100% 'clean,' whatever that means. If you could plumb 100% of the overflow through the skimmer it could only perform as well as that skimmer performed. Unless the sump flow rate is so slow that the same water is repeatedly skimmed, I do not see how you obtain any advantage or disadvantage from sump flow rate.
2. I have my refugium separately plumbed from the main flow of the sump. I run a pump from the sump to the fuge and water flows back by gravity. This way I control the flow through the area with the macroalgae. To me this separates any question regarding appropriate refugium flow from the flow of the sump.
3. The flow in the ocean is huge! I have swum in the ocean and around reefs uncountable times and I am always aware of the flow of the current or sway of the waves. It would take a dedicated effort to equal or exceed the actual ocean over reefs.

 

[ReefGeezer]

Sump flow rate is a balancing of many factors ...

Congrats on Post #1. Many don't run equipment or fuges in their sump that would influence flow speed requirements even if it mattered. I do agree that speed that causes noise is wasteful and bothersome and pumps capable of excessive speed may cause heat issues that might be a problem.

 

[Lasse]

In both your examples - the raindrops or the sushi comes from an unrestricted external source. The external source for nutrients in an aquarium is your feeding regime. Well in there - they will circulate - with help of streamers in the DT some of them will go by the return flow down to the sump. in the sump - we often have equipment that should take up different waste (proteins, organic matter, phosphate, other nutrients and so on)
Uptake rates (both according to biological uptake in the refuge, mechanical uptake in the skimmer or chemical uptake in the GFO filter) is normally not lineare to the concentration of waste compounds. The uptake rate is mostly higher in higher concentrations. All of this indicates that low flow is not the optimal way of running the sump. However - what is the optimal way to manage the flow? I think that if you have your heater in the sump and the flow that give you exactly the same temperature in the sump and display is the optimal flow for your system. Not more (a waste of energy), not less (a waste of equipment)

(phosphate is constantly being released into the system via fish grills and the faster that phosphate can reach the Refugium the more likely it is to be taken up by your macroalgae than the algae in the DT)

IMO - phosphates is not released by the gills - it is nitrogen that is released by the gills. Phosphates is released by the poop both as inorganic and organic phosphate. The organic phosphate is later converted to inorganic phosphate by bacterial mineralization.

Sincerely Lasse

 

[K7BMG]

In both your examples - the raindrops or the sushi comes from an unrestricted external source. The external source for nutrients in an aquarium is your feeding regime. Well in there - they will circulate - with help of streamers in the DT some of them will go by the return flow down to the sump. in the sump - we often have equipment that should take up different waste (proteins, organic matter, phosphate, other nutrients and so on)
Uptake rates (both according to biological uptake in the refuge, mechanical uptake in the skimmer or chemical uptake in the GFO filter) is normally not lineare to the concentration of waste compounds. The uptake rate is mostly higher in higher concentrations. All of this indicates that low flow is not the optimal way of running the sump. However - what is the optimal way to manage the flow? I think that if you have your heater in the sump and the flow that give you exactly the same temperature in the sump and display is the optimal flow for your system. Not more (a waste of energy), not less (a waste of equipment)



IMO - phosphates is not released by the gills - it is nitrogen that is released by the gills. Phosphates is released by the poop both as inorganic and organic phosphate. The organic phosphate is later converted to inorganic phosphate by bacterial mineralization.

Sincerely Lasse

I understand your correct theory that its a closed loop and that the nutrients are in fact circulating constantly, if some miss the filtration the first time they will be back for a second, third, fourt untill probabilty will land them in a filter to be consumed.

I am interpreting your statement as saying that all nutrients are in the tank and will always be in the tank with no change to the ammount as they are not introduced.

But nutrients are created by the livestock so they are constantly being produced as a new source. So internal or external introduction is mute. Or am I all wet here.

 

[Lasse]

Yes - you are at least a little wet IMO . The only new nutrients that will add to the total concentration come from the outside - your feed - your new introduced live stock- the others is only recirculated by the livestock in smaller and smaller loops.

If you ad 1 g of food - the first step will be that around 20 % will be bound as biomass - the rest as waste - some of the waste - the inorganic - will be taken up of algae - ithe organic will be ingested of animals of different type or bacteria. The algae will be eaten by grazers - they bind another 20 % - waste - 80 %. . if you do not put in enough of feed - you will have starvation after a while - if you put in too much - you will read elevated nutrient concentrations. The only exception I can see if something of your livestock will die suddenly and a lot of nutrients will be released. But it can never be more than the total input you have done during time. You will circulate the nutrients - but the total load of nutrients - both free and bound can never bee more than the one you have put into the system in form of feed or living biomass.

Sincerely Lasse

 

[K7BMG]

In both your examples - the raindrops or the sushi comes from an unrestricted external source. The external source for nutrients in an aquarium is your feeding regime. Well in there - they will circulate - with help of streamers in the DT some of them will go by the return flow down to the sump. in the sump - we often have equipment that should take up different waste (proteins, organic matter, phosphate, other nutrients and so on)
Uptake rates (both according to biological uptake in the refuge, mechanical uptake in the skimmer or chemical uptake in the GFO filter) is normally not lineare to the concentration of waste compounds. The uptake rate is mostly higher in higher concentrations. All of this indicates that low flow is not the optimal way of running the sump. However - what is the optimal way to manage the flow? I think that if you have your heater in the sump and the flow that give you exactly the same temperature in the sump and display is the optimal flow for your system. Not more (a waste of energy), not less (a waste of equipment)



IMO - phosphates is not released by the gills - it is nitrogen that is released by the gills. Phosphates is released by the poop both as inorganic and organic phosphate. The organic phosphate is later converted to inorganic phosphate by bacterial mineralization.

Sincerely Lasse

I understand the theory that its a closed system and that the nutrients are in fact circulating constantly, if some miss the filtration the first time they will be back for a second, third, fourth until probability will land them in a filter to be consumed.

Our tanks are not sealed ecosystems so that whatever is in there when it is sealed is all that will ever be.

The food we add to feed the livestock is an external source.
As well as the dosing of things oxygen, Etc.


The livestock are constantly defecating and this is a constant new source as well.

Am I all wet here as I am not understanding your argument.

 

[K7BMG]

Sorry more of a duplicate. thought the site had an issue, well it did as it added my comments to your post I quoted.
Something I did wrong I am sure. But thought it did not get through.

I will ponder your last comment I have to get my butt to work.

 

[dbowman5]

how much nutrients are added by photosynthesis or thermal conversion by the occupants of my aquarium?

 

[siggy]

Well almost 4 pages of replies and I'm at square one. I believed contact time was a good answer and not just for skimmer but my bio-bricks and media AND because I heard it here;Sorry
There must be real science on this, I like Lasse use of fish farming data.
Like I mentioned, reefers beliefs, are not always good science, but one's success with his set-up. This would be a good
Subject for an article to reset the bar. Then we can look at why tank X has a better result with slow flow or Niagara.