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

[Joekovar]

Do you drive through the carwash 50 times at full speed getting a little cleaner each time, or do you drive through at a speed that gives each machine time to do it's thing?

 

[svanur]

I have 9 times turnover return in my sump and 1000 litres pump in the refugium.Works well for my setup.But every system is different.

 

[Murica]

Less turnover rate = more detritus unable to escape the display. I'd rather make my sump larger than to see plumes of detritus getting blown around

 

[K7BMG]

I use the Triton method, and they recommend 10X turnover.
So I do my best to meet the standard.
My water volume is around 230-245.
My Apex flow meter clocks my return pump flow at an average of 1350Gph.
So I am about a 900Gph slower than the recommendation.
My returns will not handle any more than that anyway.
My skimmer is a Regal 300Ext so the sump flow matters not.
The skimmer works extremely well as I feel most recirculating units do.

Triton's recommendation of 10X I have never questioned.

So I answered the question with not sure.
In the end I know every tank is as unique as the owner of that tank is.

There is no real debate here, IMO as if you have a thriving tank the the flow you have is the right flow.

 

[Terr-c]

I am sooo happy to read this thread. I am just starting my tank (it's cycling) and because of the noise I had the pump flow turned down with a gate valve. I was worried my flow was to slow. How do you tell what your flow is per hour? I'm using a vectra S2 pump in a about 20 gallon sump for a 55 gallon tank. The overflow is a eshopp's eclipse M overflow box. Straight into the sump via pvc plumbing. My overflow is like the Herbie, straight down to the sump. I have a section with chaeto in my sump. How much flow does the chaeto need?

 

[mickeysreef <*))))<]

I believe a slower flow allows a greater amount of interaction between beneficial bacteria and nutrients. I like a higher flow on the refugium (not in sump)

 

[Steve9333]

The water being pulled into your skimmer is dependent on the pump that feeds the skimmer. The flow rate around it wouldnt matter.

Agreed! PLus with high flow sump if there is mechanical filtration in the sump like socks or roller mat they should remove more matter, which means less dissolved organic solids

 

[X-37B]

Im low flow at around 200ish gph through my 40 breeder sump feeding my 120.
I run no baffles and just dont see the need for any higher.
Internal flow is done with 4 powerheads on alternating flow.

 

[eubear]

NO! You really can't slow down the sump and keep up the water turnover rate. What you can do is keep a high turnover rate while doing things slowly with that water while in the sump such as your Protein Skimmer, Refugium, Algae Scrubber, Reactors, etc. If you slow down the water through your sump I would also expect to see a much lower ORP.

 

[WallyB]

I compare it to air cooling units. if the air is flowing too quickly through a cooling coils on a hot day, it's possible for the air to not have sufficient contact time with the cooling coils to remove heat and so you end up blowing warm air back in. Slow the flow, and the longer contact time takes out the heat and now cool air feels great.

IMO, contact time with the the skimmer algae rock etc mean the water flowing back into the DT is devoid of the stuff you want removed. None of the above filtration is 100% instant

This all is premised on being able to test the incoming water against the outgoing, It's all guess work otherwise

I voted NOT SURE (Since it depends on the System setup. Many factors)

I was thinking I agree with above Post that Slower for longer Contact Time concept makes sense.

What's more important is contact time in a Skimmer. (Same applies various reactors, and refuges)
The water flowing thru the sump, slow or fast is same consistancy in tank, sump (where skimmer is located).
Maybe the DT has a bit more nutrients during feeding time, and less during night when fish are asleep.
However Flow doesn't matter for the skimmer drawing in water.

The skimmer draws the dirty water (same amount, regardless of flow thru sump), and outputs clean (lower nutrient/particulate) water at the ouput of the skimmer.

Yes, slower contact time with Live rock in SUMP could have some beneficial value. That rock is usually located somewhere in sump with less direct sump-passthru-flow anyway.

Slow would also be beneficial for filter socks, floss, to catch small particulates better (if that is the goal), and not be blasted thru.

I'm not sure about the overall value of Sump Flow Rate (so long is it not crazy high, or crazy low), when you consider the full day of closed system cycling, so long as the DAILY NUTRIENT EXPORT, can keep up with the DAILY NUTRIENT IMPORT.

Also another factor for Sump Flow Rate (or Return pump rate), is if that flow determines a major portion of the flow in DT, and not some other Circulation pump(s) in DT. In that case, higher flow would be better.

 

[Reefdom]

I don't think it matters in the slightest provided there is enough flow for sump mounted heaters to maintain consistent water temperatures. If that "requirement" is met, the rest is irrelevant.

Exactly this. If you can maintain consistent temp in tank and sump, that’s thecturnover you need, whether higher or lower flow, this should be main focus. When I tried to slow my sump turnover I reached s point where the tank was a little cooler than the sump as the heated water wasn’t getting into the tank and back out before cooling down, so I slowly increased the flow until it was consistent and left it there.

 

[SPR1968]

I’m going for a rate of around 3 x total system volume, or slightly less through the actual sump itself to maximise contact with the media down there In my new 530g system

The display is a different matter with 2 MP60‘s and an MP40 in addition to an Abyzz a200 return provides a massive amount of water circulation in there, but calmer through the sump.

 

[Lasse]

Let me put to death one very (IMO) common myth - lower flow have importance because it increases the contact time. IMO it has not. We are talking about recirculation systems - one missed molecule or compound will come back again. You can´t only count one passing cycle - you must count all throughput for a specified time interval. A throughput of 24 times an hour give the same total contact time as throughput of 1 time an hour. A faster throughput will also contribute to a faster treatment of newly produced waste in the display tank. The theory of lower flow - better treatment because of one long contact time is only valid for pure run through systems like waste water plants.

As an example - a higher flow through the biofilters in recirculating fish farms gives a better result than a slow flow when the volume of the filters are the same.

I have a throughput of 2,500 l/h in my 300 l display tank ( > 8 times 8 times per hour) My refuge is 30 l (>80 times/hour) My skimmer apartment 30 l (> 80 times/h) and my return pump apartment 15 l (> 160 times an hour) My skimmer have a throughput of around 1500 l/h. My biofilter/ bacterial food producer (in the return pump section) process around 500 l/h. The biofilter have higher flow during some minutes in the night in order to give out bacteria (as food) for my corals.

Sincerely Lasse

 

[K7BMG]

I am sooo happy to read this thread. I am just starting my tank (it's cycling) and because of the noise I had the pump flow turned down with a gate valve. I was worried my flow was to slow. How do you tell what your flow is per hour? I'm using a vectra S2 pump in a about 20 gallon sump for a 55 gallon tank. The overflow is a eshopp's eclipse M overflow box. Straight into the sump via pvc plumbing. My overflow is like the Herbie, straight down to the sump. I have a section with chaeto in my sump. How much flow does the chaeto need?

There are a couple of ways to determine flow rates.
You can take the charts for all plumbing parts and do the math.
Manufactures pump flow chart will tell you how many gallons per hour it will produce at a given height called Head Pressure.

Just an example.
Pump A using 3/4 plumbing at a height of 60 inches will provide 100 gph.
Now you have to deduct the fittings.
There are charts for these as well.
So a 45 degree will reduce flow by 1 gph a 90 by 3 gph.
So at a head height of 60 inches and two 45 and two 90 fittings
will reduce the flow by 8 gph resulting in a overall 92 gph.
In the end I feel this is the least accurate method but it will get you close.

Second way you can take the pump and pipe assembles as it will be used for your tank, calculate the gallons of your tanks actual volume.
Interior dimentions to be more accurate. Length times width times actual water height devided by 231 will give you the real gallonage of the tank.
Turn on the pump and time how long it takes to fill the tank.
So when you find out your 150 gallon tank only really holds 137 gallons then hit the on button and the stop watch.
If it took 2 minutes to fill the tank than its 137 devided by two and multiplied by 60 137 / 2 = 68.5 times 60 = 4 110 gph.

Or you can install a flow meter on the line.

 

[K7BMG]

One can use the windshield theory.

Its raining and you are at a stop light.
The flow (rain) hits your windshield (algae) and no wipers are needed. Droplets equating to unwanted nutrients

Now you go 60mph through the rain and so many rain drops (unwanted nutrients) is hitting your windshield (algae) you need your wipers.

The faster you go the more nutrients will make contact period.
Volume vs time.

Nutrients are particles that get stuck in the algae, the more particles the abundance of food in on the algae. Once stuck in on the algae contact time is there.

 

[Lasse]

One can use the windshield theory.

Its raining and you are at a stop light.
The flow (rain) hits your windshield (algae) and no wipers are needed. Droplets equating to unwanted nutrients

Now you go 60mph through the rain and so many rain drops (unwanted nutrients) is hitting your windshield (algae) you need your wipers.

The faster you go the more nutrients will make contact period.
Volume vs time.

Nutrients are particles that get stuck in the algae, the more particles the abundance of food in on the algae. Once stuck in on the algae contact time is there.

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

 

[atoll]

Consider this and am only stating facts as I know them to be and my experiences.

My first sump had a turnover of once every 3 hours.
I had lots of living rock in the DT with some now very old Tunze air cooled pumps 4002 and 2002, some might recall them, providing flow, great pumps BTW.
I grew Caulerpa in the DT later in the sump.
I have an old Tunze venturi skimmer in the sump which worked very well.

OK we didn't keep much in the way of SPS back then mainly LPS and softies. These corals did well.
I had a magnifica anemone in my DT with 3 common clowns. I had dwarf Angel's that spawned along with mandarins. BTW, This was at a time when magnifica anemones were regarded as a very difficult anemone to keep, some "experts" of the day said it was impossible to keep one more than a few weeks in the home aquarium. I had that nem for a good few years before I broke the tank down and moved house.

My clowns spawned constantly next to that nem. A pic of that anemone with clowns appeared on front cover of Albert Thiel's book 10 easy steps here in the UK.

The tank was very successful and people came from all over to see it including professional aquarists.

Remember this was with a tank with a flow through the sump of just once every 3 hours. The tank and sump etc appeared in Practical Fish Keeping here in the UK. Many people couldn't get their head round how successful it was and many considered it the best domestic tank they had ever seen.

 

[Terr-c]

There are a couple of ways to determine flow rates.
You can take the charts for all plumbing parts and do the math.
Manufactures pump flow chart will tell you how many gallons per hour it will produce at a given height called Head Pressure.

Just an example.
Pump A using 3/4 plumbing at a height of 60 inches will provide 100 gph.
Now you have to deduct the fittings.
There are charts for these as well.
So a 45 degree will reduce flow by 1 gph a 90 by 3 gph.
So at a head height of 60 inches and two 45 and two 90 fittings
will reduce the flow by 8 gph resulting in a overall 92 gph.
In the end I feel this is the least accurate method but it will get you close.

Second way you can take the pump and pipe assembles as it will be used for your tank, calculate the gallons of your tanks actual volume.
Interior dimentions to be more accurate. Length times width times actual water height devided by 231 will give you the real gallonage of the tank.
Turn on the pump and time how long it takes to fill the tank.
So when you find out your 150 gallon tank only really holds 137 gallons then hit the on button and the stop watch.
If it took 2 minutes to fill the tank than its 137 devided by two and multiplied by 60 137 / 2 = 68.5 times 60 = 4 110 gph.

Or you can install a flow meter on the line.

7278083 Thank you, I will give that a try.

 

[Grant Beyleveld]

One can use the windshield theory.

Its raining and you are at a stop light.
The flow (rain) hits your windshield (algae) and no wipers are needed. Droplets equating to unwanted nutrients

Now you go 60mph through the rain and so many rain drops (unwanted nutrients) is hitting your windshield (algae) you need your wipers.

The faster you go the more nutrients will make contact period.
Volume vs time.

Nutrients are particles that get stuck in the algae, the more particles the abundance of food in on the algae. Once stuck in on the algae contact time is there.

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

I agree with @Lasse on this one. If nutrients are not removed by your sump filtration on the first pass, they'll be removed when they circulate again (if you've got 10X flow, that'll be in about 6 minutes!) - so high flow and low flow don't really make much difference I wouldn't think.

Where it would matter is if your turnover rate is so low that waste products build up in the DT while the sump is sparklingly clean because it's being repeatedly filtered. But I would imagine this would only happen if the turnover rate was significantly low, in the order of much less than 1X.

I don't think it matters in the slightest provided there is enough flow for sump mounted heaters to maintain consistent water temperatures. If that "requirement" is met, the rest is irrelevant.

This point resonated with me - as long as your DT and your sump maintain equilibrium then you're probably fine. Put differently, if the sump is removing waste from the water faster than your return pump brings in waste then there's an inefficiency there. Temperature might be a good proxy measure for this, or one could test NO3 or PO4 in the DT vs the sump. They should be about the same, generally.

As for the higher limits, I don't think there is a limit, practically speaking. If you can achieve 20X turnover and it suits your sump (for example, you don't have miracle mud in there!) and your DT (you're using your return as your primary flow, or whatever) then go for it. Your filtration is not going to cease to work because it "missed" the nutrients as they whizzed by. It'll get them next time, I promise.

 

[oceans garden aquaculture]

I have always found the natural estuary simulation to be most beneficial. Low flow allows filter feeders to thrive as well as algae. Pods seem do be much more dense imo.