Volume and velocity question

[handyman]

My setup:
I have a customsealife T4 pump at 0’ its rated at 1446gph at 6’ its rated at 1200gph

I’m using 1” tubing, vertical length = 4.75’, horizontal length = 4’, 1 right angle, and the tubing bends over a 2’ length to make another right angle so I figure 1200gph is about what I’m getting, maybe 1000gph worst case.

The T4 has an ID “inside dimension” of 3/4" both in and out of the pump.
I’m using 1” ID tubing with 1” hose barb connectors that have a 3/4" ID
This goes to a 1” T then to two 3/4" reducers those go to two 3/4" ID Flexible Ball-Socket Joint to a 3/4" ID nozzles.

So at this point IMO I have a 3/4" output from the pump going through 1” and 3/4" plumbing split to two 3/4" nozzles, yes.
The water movement in the tank at this point is bad the turnover through the refugium is awesome.

I then placed cutoff pieces of 3/4" hose barb connecter inside of the nozzles, these have an ID of 1/2". The water movement in the tank was better the turnover in the refugium was the same.

I wanted more water movement in the tank.

I then placed cutoff pieces of 1/2" hose barb connecter inside of the nozzles, these have an ID of 3/8". The water movement in the tank is awesome and the turnover in the refugium appears to be the same.

Sorry for the length of this post.

What was my question, oh what do you think.
The water right out of the nozzles is a little turbulent is this ok?
Thanks

 

[Len]

I'm having a little tough time figuring out how your pump/pipes are configured. A little turbulence is fine. The idea is to move as much water with as little velocity as possible. Turbulence is fine so long as the corals aren't being whipped about violently by the current.

 

[Anonymous]

I am as confused as the first time I read it after going thru the post 4 times... :? Maybe rewording it a bit... at least it will give it a bump...

 

[handyman]

Lets start with this pic
http://reefcentral.com/forums/attachmen ... id=1557070

 

[handyman]

all slip adapters and T4 have an ID of 3/4"

 

[ChrisRD]

Assuming we use your low number of 1000 GPH, and if I'm reading you right, you have two returns, that's roughly 500 GPH at each return (if the flow is split evenly).

At 500 GPH, a 3/4" ID outlet will produce about 6 feet per second (FPS).
A 1/2" ID outlet will produce about 13-14 FPS.
A 3/8" ID outlet will produce about 24 FPS.

FWIW, flow velocities on a natural reef are more on the order of like 4 FPS.

Make sure you don't place any corals directly in front of those outlets if you're going to leave them that restricted.

 

[handyman]

Assuming we use your low number of 1000 GPH, and if I'm reading you right, you have two returns, that's roughly 500 GPH at each return (if the flow is split evenly).

At 500 GPH, a 3/4" ID outlet will produce about 6 feet per second (FPS).
A 1/2" ID outlet will produce about 13-14 FPS.
A 3/8" ID outlet will produce about 24 FPS.

FWIW, flow velocities on a natural reef are more on the order of like 4 FPS.

Make sure you don't place any corals directly in front of those outlets if you're going to leave them that restricted.

Chris,
Thank you,
I measured the flow out of 1 nozzle last night and I was getting 375gph. How many fps is that and how did you come to this conclusion what is the calculation

 

[handyman]

I just reversed engineered your calculation and came up with 4.5pfs is this correct

 

[ChrisRD]

I just reversed engineered your calculation and came up with 4.5pfs is this correct

Yes, for 375 GPH through a 3/4" nozzle, that's correct.

what is the calculation

The basic equation is Q=VA, where:
Q = Flow (CFS, cubic feet per second)
V = Velocity (FPS, feet per second)
A* = Area (cross sectional area in square feet)

* = In our case we're talking pipes, so the cross sectional area is a circle. Area of a circle = 3.14159 * R^2, where R = radius

Also, to convert GPH into CFS you need to divide by 27,000 (7.5 gallons in a CF, 60 minutes in an hour, 60 seconds in a minute, ie. 7.5 X 60 X 60 = 27,000).

HTH

 

[handyman]

Yes, for 375 GPH through a 3/4" nozzle, that's correct.
HTH

That was with the 3/8" nozzle, I haven't measured the 3/4" or the 1/2" nozzles yet.

 

[ChrisRD]

That was with the 3/8" nozzle, I haven't measured the 3/4" or the 1/2" nozzles yet.

375 GPH through the 3/8" calculates to about 18 FPS.

 

[handyman]

375 GPH through the 3/8" calculates to about 18 FPS.

but isn't that right out of the nozzle the further from the nozzle it gets the slower it get I think

 

[liquid]

You know...you could be thowing all of this data into the Excel spreadsheet found here: http://www.reefs.org/library/pumps It'll spit out just about any info you want based on your plumbing and pump selection.

Shane

 

[ChrisRD]

but isn't that right out of the nozzle the further from the nozzle it gets the slower it get I think

True.

You know...you could be thowing all of this data into the Excel spreadsheet found here: http://www.reefs.org/library/pumps It'll spit out just about any info you want based on your plumbing and pump selection.

True.

 

[handyman]

You know...you could be thowing all of this data into the Excel spreadsheet found here: http://www.reefs.org/library/pumps It'll spit out just about any info you want based on your plumbing and pump selection.

Shane

Yes, this is great but it dosen't take into account the 1" hose barbs that have 3/4" ID's

I increased the nozzle to 1/2" openings still have good movement in the tank! I need to measure the gph

 

[esmithiii]

Keep in mind that the water slows as it diffuses in the tank, so 20 fps at the nozzle may equal 4fps a foot away.

Ernie

 

[Anonymous]

Ernie nailed this entire thread.

The best way to approach this is to decide how much flow you need want at the coral's position then work backwards to the pump.

Average instantaneous flowrate at a specific location in the ocean may be around 4 FPS, however, realize that this is a uniform, broadcast flow over an area like a coral head. In a tank, there are stratified areas of high flow and relatively stagnant areas.

The goal of any internal flow design is to produce a gentle turbulent flow throughout the entire tank.

That said, it wouldn't matter if you had a T1000 pump if your flow is not dispersed in a way that creates a rolling turbulent flow in the tank.

People get hung up on turnover rate, assuming it must come from the main return pump. For a 100g tank, you can get away with 500g/hr or less of actual turnover with the filter, as long as you augment flow inside the tank with other flow options like power heads. In this example, placing 4 maxi-jet 1200s on a wavemaker will achive about a 1000g/hr internal turnover, plus the 500g/hr from the return. 1500g/hr equates to 15 tank volumes per hour, which is more than adequate.

If you're hellbent on figuring out how much headloss occurs due to rise and run, diameter, and fitting types, call the manufacturer and ask for the headloss coefficients for the type of material used. They've probably got more info than you'd care to muddle thru. BTW, flex tube is nice to work with, but it is also one of the less efficient types of plumbing. It tends to have a lot of form and skin drag which increases headloss=reduces flow.

Hope this helps.

 

[Anonymous]

>The goal of any internal flow design is to produce a gentle turbulent flow throughout the entire tank.

I dont agree with this, I never liked gentle flow, and now that I've snorkled in hawaii, it enforced this fact, I could barly hang on to the rock when looking at corals!

 

[ChrisRD]

The water right out of the nozzles is a little turbulent is this ok?

Make sure you don't place any corals directly in front of those outlets if you're going to leave them that restricted.

The point I was trying to make was that it could be damaging to corals to subject them to very high velocity flow directly in front of the restricted nozzles.