Return pump flow rate recommendation

[Kilo]

Hi Everyone,
Can someone advice what is the min flow rate required for a 85G (3ft x 2ft x 2ft). My height of head is 5ft
I read somewhere the rate of turnover should be around 10x. so does that mean i need to get a pump that can achieve 850GPH at head height of 5ft?

Thanks in advance

 

[Reefpro]

Yes that is correct. With that being said, some people prefer more and some people prefer less. I also think if you turn over too much water, your dwell time for skimmer is a lot less and the performance of skimmer is affected. Just my .02

 

[mcarroll]

+1

2x to 4x the display volume it ordinarly plenty.....maybe 5x if you want to be extra conservative.

So get a pump that delivers from 170 GPH to 340 GPH....perhaps as much as 425 GPH and you should be all set.

And yes, your description of how you size your pump is correct.

Find a flow curve like these for your preferrred pump and conpare your head loss to the chart.

Use a headloss calculator if you have anything more complicated than a simple, vertical shot up to the return. Elbows and other fittings as well as vertical lift have a significant impact on flow. Estimate conservatively if you're just estimating.

Here's a calculator: http://www.freecalc.com/fricfram.htm

 

[Kilo]

Display Tank =~339litres
Sump Tank = ~ 79litres
Total=418litres
Turn= 6x
flowrate 2508LPH
Head = 5ft
Working back on Sicce chart, syncra 4.0

Most likely will be getting the Syncra 4.0 as my main return pump and backup pump which will feed the chiller & reacter back to Display tank.

Thanks everyone. Let me know if there are any other considerations

 

[mcarroll]

• You don't mention it, so I'll assume you're using 1" PVC plumbing.
• 85 gallons x 6x (waste of 1x or 2x IMO) is 510 GPH
• 510 GPH = 8.5 gallons per minute
• 1 entrance
• 1 exit
• 1 90º short-radius elbow (the standard type)
• 0 reducers

Here's what I get:

Liquid Friction Pressure Loss
Pressure Loss (psi): 0.23 Head Loss (ft): 0.5
Line Number: 1", 1" outlet, 1 90º, no reducers
Date: 8/16/2016
Nominal Pipe Size: 1
Pipe Schedule: SCH 40
Flow Rate (gpm): 8.5
Viscosity (cP): 1
Specific Gravity (water=1): 1
Temperature (F): 70
Pipe Roughness (ft): 0.000016
Actual Pipe ID (in.): 1.049
Fluid Velocity (ft/sec): 3.16
Reynolds Number: 25626
Flow Region: Turbulent
Friction Factor: 0.025
Overall K: 3.38
Piping Length (ft): 5
Short Radius Elbows: 1
Pipe Entrance: 1
Pipe Exit : 1​

That makes your 5' of lift into 5.5' or 1.68 meters.
510 GPH = 1930 liters per hour

So still using that flow chart for example, a Syncra 3 or 3.5 would be all it takes, even for 6x.

A Syncra 2.5 would actually work fine and do the job well at around 3x (~900 LPH) to 4x (~1200 LPH) flow.

Overkill in this area really doesn't buy you much in the way of bang for your buck and can cause issues with noise....smaller pumps and smaller flows are always more quiet and less trouble (and cheaper).

 

[mcarroll]

Not sure what's marketed where you are, but it appears from drfostersmith.com that we only have the old QuietOne pumps (which apparently Sicce historically made and which I liked very much) and not the Syncra or Silence branded pumps.

You are not here, however, so your scene may be totally different.

 

[Kilo]

So still using that flow chart for example, a Syncra 3 or 3.5 would be all it takes, even for 6x.

A Syncra 2.5 would actually work fine and do the job well at around 3x (~900 LPH) to 4x (~1200 LPH) flow.

Overkill in this area really doesn't buy you much in the way of bang for your buck and can cause issues with noise....smaller pumps and smaller flows are always more quiet and less trouble (and cheaper).

Mcarroll,
Thanks for taking the time to explain the calculation. you are right, a syncra 3 or 3.5 would be sufficient.

Not sure what's marketed where you are, but it appears from drfostersmith.com that we only have the old QuietOne pumps (which apparently Sicce historically made and which I liked very much) and not the Syncra or Silence branded pumps.

You are not here, however, so your scene may be totally different.

I'm not from the States but from Singapore. Syncra is from Sicce. Here's the link:
http://www.sicce.com/prodottiLista_eng.php/tipologia=syncra-silent/idtipo=4/idcat=1

You can also find it in Marine Depot and is available globally

Thank you

 

[mcarroll]

Great!

 

[Uliulimaka]

Danner mag 9.5 would be fine on that tank.