# Plumbing question - flow rates



## PaNiK (Dec 10, 2003)

Im currently in the process of a 90 gallon drilled tank build. I have some questions I was hoping to get some help on.

I bought the tank used and it was plumbed with a 1" drain. Slip tank side, barbed sump side

The return bulkhead is 3/4 in slip tank side, 3/4 barbed sump side.

I have a rio* 3100 return pump

What kind of flow rate can I reasonably expect?


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## fusion (Jun 21, 2012)

A 1" drain has a max flow of 600 gal/hr, any bends or other restrictions will bring that down, by how much im not sure, my tank is the same as yours, 1" drain and 3/4" return so ill be watching this also lol


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## PaNiK (Dec 10, 2003)

So trying to figure out a way to make the 3/4 inch return line a 1" line would be pointless because of the drain limitations?

So that's max 6.6 x turn over then? I know there has been a lot of advocates of at least 10x turn over. That may be something to consider.


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## fusion (Jun 21, 2012)

PaNiK said:


> So trying to figure out a way to make the 3/4 inch return line a 1" line would be pointless because of the drain limitations?
> 
> So that's max 6.6 x turn over then? I know there has been a lot of advocates of at least 10x turn over. That may be something to consider.


From what iv read and researched, the 10x turnover dont realy apply to sumps, if you look at the flow rates on the commercial ones they are no where near 10x turn over for the rated size. But i could be wrong, hope someone with some experience on sumps chimes in.


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## Koteckn (May 16, 2012)

I have also heard/read the same things that fusion is talking about. As always though, the more water that is cleaned, turned over, the cleaner your water will be. I used a 1" drain line so when im topping off the main tank, the water goes to the sump rather than overflowing my tank. This is an easy way to get your sump water level where you want it without having to worry about overflowing either. I dont have check valves on my plumbing, which I should (too excited to get my tank up). If you want your tank completely quiet, some more research should be done. I like the ambient water slushing around because I have a spray bar so I wanted that water movement sound. It's really not that loud and you normally cant hear it unless you are right next to the tank.

My rio 3100 is moving about 600-650gph in my 75 and my water is crystal clear now. Even though im not at the 10x turnover rate.

Cmon panik, get this thing done!

Howie


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## PaNiK (Dec 10, 2003)

I'm trying howie!

I think I'll give it a shot running it as is. If it doesn't work out I'm kicking around the idea of using both holes as drains, and running a 1" return line over the back of the tank


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## fusion (Jun 21, 2012)

I wouldnt be worried about your return line only being 3/4", bigger/smaller holes in your spray bar will allow you to regulate your flow


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## jcabage (May 29, 2012)

I have the same setup with my 90 bulkhead-wise. I built a sort of stockman standpipe hybrid with small holes drilled into the standpipe and a sponge surrounding it up to the bottom of the stockman. I know it's not standard to have a full siphon running without an emergency drain, but the sponges prevent anything from entering the pipe, and I just clean them as I notice the water level in the overflow rising a bit. With a full siphon running, you can move much more than the anticipated gravitational drain. If you were to consider using two drains in your overflow, I would definitely look into creating a full siphon. There is no need to have two gravitational drains IMO. A standpipe (especially siphoning) will reduce your noise dramatically. My overflow water level sits about 6" below that of the DT, and all I can hear is the trickle from the fall. In total, I think I spent $22 re-plumbing my tank to include the stockman as well as a ball valve outside of the tank. Well worth it at my house 



fusion said:


> A 1" drain has a max flow of 600 gal/hr


 - This is a gravitational number only, and is based on an average with a particular schedule of pvc and a particular drop height. Check out this chart.









http://saltwater.aquaticcommunity.com/2 ... ng-basics/

Also, note what a 3/4" pipe can move when pressurized (as from your pump). It can handle quite a bit more than you might expect


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## fusion (Jun 21, 2012)

So his drain is still only 600 gph max with full siphon, i belive he has a Durso type standpipe and will be able to choke it back if needed, that chart helps as it shows a 3/4" pipe will pump more than he will need to keep the levels in the sump stable, just need to play with the outlets to equalize the input/output in the sump without choking the pump back too much.


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## jcabage (May 29, 2012)

There is a difference in letting water run through the pipe much like it would run down the drain in your shower (just through gravitational pull), and creating a siphon effect by adjusting the air allowed into the drain and essentially pulling water down. Here's some math concerning a 100g tank with a 1" bulkhead. I won't take credit for it at all (I found it while looking into this same situation for my tank on another forum), but you get the idea.



> Maximum flow, as derived from the fluid energy equation, for 1" slotted stand-pipe in 25" deep tank. Assuming no friction loss for smooth plastic pipes, and a flow coefficient of 1 for rough flow. Assuming datum at tank base.
> 
> 25"[(water height above lowest possible entry into overflow)] = -10" [(verticle length of plastic pipe below bulkhead)] + V^2/(2G) [(avg. velocity squared divided by twice gravity)]
> 
> ...


Reports of people using a siphoning drain and getting well over 600 gph through a 1" bulkhead are not at all uncommon. There was a guy in the same thread pushing 700+ through his 1" drain, and only foregoing a larger pump because of the excess heat that it produces. He referenced the length of downtube below the bulkhead as the major contributing factor in creating a powerful siphon. Either way, moving more than 600 gph down a single 1" drain is completely legitimate under the right circumstances. At least from my research :thumb:

For more reference: Here is the video I used when building my stockman. Note 4:40


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## PaNiK (Dec 10, 2003)

That's great info! Thank you very much. As for the return line, any idea what kind of restriction, if any using a 3/4in line would cause?


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## PaNiK (Dec 10, 2003)

The reason I ask is, my pump only. Came with a 1" output. When I emailed them asking about getting a 3/4". They said they only recommended using a 1" as using anything smaller might cause noisy operation. Would the noise be the only downside?


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## jcabage (May 29, 2012)

I would imagine it wouldn't have any large effect on the pump. It might lose a little power, but lots of things factor in to that as well. The most important aspect to consider would be the head height that it will have to travel back to your tank. It may not even be noisy. Then again, large pumps tend to have a pretty good hum over time anyway from what I have seen. Check out the plumping department at Lowe's, and I'm sure you will be able to find some kind of adapter to suit your needs and make it 3/4". I'd be sure to change the diameter somewhere other than the mouth of the pump though, so that you don't permanently alter it. Remember, PVC cement plays for keeps :thumb:


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## fusion (Jun 21, 2012)

Yes great info, i like that stockman, would take up less room than the Durso.

Panik, hope you dont mind me intruding on your thread here, your asking the questions im also wondering about


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## PaNiK (Dec 10, 2003)

It's all good man, it's on topic. And your questions have helped move things along. You've been a good contribution


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## fusion (Jun 21, 2012)

PaNiK said:


> It's all good man, it's on topic. And your questions have helped move things along. You've been a good contribution


Ty :thumb:

For your return, you could come out of the pump with 1" hose, your going to need a valve in that line so a 1" valve connected on the sump side with a 1" hose fitting that screws into the valve, other side to outlet a screwed reduced hose fitting to 3/4" then 3/4" hose to your spraybar, lows sell all of this, the hose fittings are in the hose section, not the pipe fitting section.


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