1" PVC Flow Rate?

KoleTang

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What is the flow rate of 1" PVC? It is a full siphon herbie and will be going down about 12' if that changes anything.
 

Jlobes

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generally, the number you most hear referred to is about 900gph. of course, there are variables and such, this is just a rough guideline.
 

Reefing Madness

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Last I checked, a 1" overflow would acommodate 600gph.

GPHpipe.png

http://www.reefaquarium.com/2012/aquarium-plumbing-basics/
 
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AZDesertRat

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With the proper water/air mixture and standpipe and plumbing design you can bump the 600 GPH up considerably. I am pushing 900 GPH with a single 1" Stockman standpipe with straight thru plumbing with elbows or restrictions.
 

Ron Reefman

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Last I checked, a 1" overflow would acommodate 600gph.

GPHpipe.png

Aquarium Plumbing Basics - Reef Aquarium

Not sure I trust your source. I've always used 900-1000gph for 1" pipe. Here is what I go by:


[SIZE=-1]Assume Gravity to Low Pressure. About 6f/s flow velocity, also suction side of pump[/SIZE][SIZE=-1]Assume Average Pressure. (20-100PSI) About 12f/s flow velocity[/SIZE][SIZE=-1]Assume "High Pressure" PEAK flow. About 18f/s flow velocity*[/SIZE]
Sch 40 Pipe SizeID
(range)
ODGPM[SIZE=-2]
(with minimal pressure loss & noise)[/SIZE]
GPH[SIZE=-2]
(with minimal pressure loss & noise)[/SIZE]
GPM[SIZE=-2]
(with minimal pressure loss & noise)[/SIZE]
GPH[SIZE=-2]
(with minimal pressure loss & noise)[/SIZE]
GPM[SIZE=-2]
(with significant pressure loss & noise)[/SIZE]
GPH[SIZE=-2]
(with significant pressure loss & noise)[/SIZE]
1/2".50-.60".85"7 gpm420 gph14 gpm840 gph21 gpm1,260 gph
3/4".75-.85"1.06"11 gpm660 gph23 gpm1,410 gph36 gpm2,160 gph
1"1.00-1.03"1.33"16 gpm960 gph37 gpm2,220 gph58 gpm3,510 gph
1.25"1.25-1.36"1.67"25 gpm1,500 gph62 gpm3,750 gph100 gpm5,940 gph


GPM/GPH Flow based on PVC Pipe Size, ie, How much water can flow through Sch 40 Pvc Pipe Size 1/2" 3/4" 1" 1.5" 2" 2.5" 3" 4" 6"
 
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FF337

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I dont trust those charts

Using a pitot gauge, Pressurized @ 200 psi. 200 feet of 1" rubber lined cloth jacketed and rubber coated hose can flow ~60 gallons per minute from a 1260 gpm single stage pump.

I would imagine Sch 40/80 pvc would be in a similar category since there is less friction due to the smooth wall.

Yes in this situation we are talking low volume low pressure and even gravity fed but the question what is the flow rate of a 1" pipe.
 

AZDesertRat

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Very conservative numbers. A short section of 1" with minimal restrictions will gravity flow much greater than 600 GPH when you have the proper air mix.
 

Mike J.

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Very conservative numbers. A short section of 1" with minimal restrictions will gravity flow much greater than 600 GPH when you have the proper air mix.
Yes, I totally agree, when you have a siphon established. When you lose that siphon I wouldn't risk having to drain more water than a 1" pipe can handle. It's always better to err on the safe side. Also, a drain is much quieter when it is not running at max. capacity - I like quiet.
 

AZDesertRat

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I have never had an issue reestablishing a siphon in a power outage in the 9 years I have been running a single 1" standpipe on pumps between 750 and 900+ GPH at 4 feet of head.
 
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KoleTang

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Just to clarify, this is 1" pipe going down about 12 feet into my basement. It is a herbie setup (full siphon).

So I am wondering how much flow I can expect to get with just gravity, no pumps.


If I go from 1" to 1.5" - 2" then back to 1" will it increase the flow at all?
 
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Ron Reefman

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Just to clarify, this is 1" pipe going down about 12 feet into my basement. It is a herbie setup (full siphon).

So I am wondering how much flow I can expect to get with just gravity, no pumps.


If I go from 1" to 1.5" - 2" then back to 1" will it increase the flow at all?

The short answer is, no.
It will help maximize the flow thru the 1" section if you back up some water in the 1.5" or 2" section of pipe. But it won't really improve the flow rate beyond what gravity can do thru a 1" pipe.
 

AJP279

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generally, the number you most hear referred to is about 900gph. of course, there are variables and such, this is just a rough guideline.
Awesome...was just looking for this!
 

ca1ore

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So the thread is 6 years old. Regardless, 1” siphon with significant drop will move more than 1,000 GPH. Mine, with about 10’ of negative head easily handles 1,100.
 

AJP279

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So the thread is 6 years old. Regardless, 1” siphon with significant drop will move more than 1,000 GPH. Mine, with about 10’ of negative head easily handles 1,100.
Awesome...the pump I ordered is just over 1000 GPH; it's not the one for long term, but it will do to start.
 

garyfri

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The short answer is, no.
It will help maximize the flow thru the 1" section if you back up some water in the 1.5" or 2" section of pipe. But it won't really improve the flow rate beyond what gravity can do thru a 1" pipe.
Ron,

I know this post is old by can you explain "help maximize the flow through the one inch section". I have a bean animal and the full siphon overflow is 1 inch. I was going to increase it to 1 1/2" as I saw a youtube where they were recommending all drain to be 1 1/2 for large aquariums. It seems that the 1" inch pipe will restrict it so is it even worth going 1.5 inch. Thank you for the advice
IMG_20200815_225021.jpg
.
 

Ron Reefman

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Gary, if you increase the size of the bulkhead and ALL the pipe in the drain to 1 1/2" it will flow 1500 gph vs 960 gph with a 1" pipe.

flow.jpg


If you increase the drain to 1 1/2" pipe but still have a 1" section of pipe or bulkhead or union, then the entire system will run at the 1" diameter flow rate of 960 gph. The only way you can get more flow through a 1" pipe is to apply pressure. If the drain were in the very bottom of the tank with 2' of water pressing down on it, it would flow a little faster (the water pressure behind the weir/overflow on even a bulkhead at the very bottom would be small. The other way is to use a pump, which is impractical when trying to get water from the tank to a sump... not impossible, but I don't know anybody who does it.

Does that help?
 

KStatefan

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Can someone explain to me how this chart works for gravity flow. The chart is assuming 6 feet per second flow. The flow is going to change with the total drop of the water.

Bernoulli’s Principle formula is Velocity = Sqrt(2*g*h) which show the velocity is going to change with height.
 

ca1ore

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Can someone explain to me how this chart works for gravity flow. The chart is assuming 6 feet per second flow. The flow is going to change with the total drop of the water.

Bernoulli’s Principle formula is Velocity = Sqrt(2*g*h) which show the velocity is going to change with height.

Not well I think LOL. Perhaps a good starting point but as somebody that runs a basement sump the numbers are low.
 

KStatefan

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Not well I think LOL. Perhaps a good starting point but as somebody that runs a basement sump the numbers are low.

That is my thinking but this chart gets quoted here all the time.
 
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