Overflow pipe sizing?

[Secondgen]

Just wanted some opinions on this. I am just about ready to setup my 50 breeder with an internal overflow, and am trying to decide between 1 inch, or 1 1/2 inch overflow piping. This will be split before it reaches the sump into two 3/4 inch lines that will emty into the fuge, and skimmer sections. Please let me know what everyone thinks. I am going to price this stuff out tonight. Thanks

[slandis3]

I have 1.5" overflow pipes on my tank. Its nice to know i can increas the flow with the bigger pipes.

[Joel]

You could do a 1.5" stand pipe or make a "Durso" type stand pipe, that might make the drain a little quieter however, it will have to be reduced to a 1" pipe because that is what size bulk head will be installed in the hole in the tank. To do this it is best to use a bell type reducer versus the type you can find at Lowes or home depot. The bell type is a smooth transition from 1.5" to 1", makes it much quieter and smooth flowing. Or just buy a Durso style stand pipe with the smooth reducer type fitting buily into it. I don't think that there would be a major advantage to doing a 1.5" stand pipe if your not going to use a bell type reducer.

Another thing I would re consider is to not reduce your 1" drain to two 3/4" drains. My concern would be reduced water flow and noise. Often smaller diameter drain hoses can start a siphon because the water can completly fill the inside of the tube. When this happens you can get all kinds of chugging and burping going on with your drain, it can be pretty obnoxious.

In my opinion and in my experience, A 1.5" "durso" or durso style stand pipe reduced to 1" at the bulk head and then "t"-ed into two 1" drain lines to your sump would be the way to go.

Joel

[slandis3]

I did the Durso style on mine as well. They go form 2" to 1.5" with the bell adapters. I know they will handle the 2400gph pump i have on there now with no problems.But on a 50g you probably dont need that much flow. You can save a good amount of money doing the 1" setup.

[Viggen]

A 1 in draing can flow over 1000 gph thus I would think the only reason to go with a 1.5 in pipe is if you are using a lot more flow then that. 

[Joel]

I don't agree that a single 1" drain will move 1000 GPH, about 500 to 600 GPH is about as much should be run thru a 1" drain.

Building or buying a 1.5" to 1" Durso style stand pipe is pretty cheap, I think the pre-fab ones I sell are like 30 bucks. Building one is probably close to half that.

The primary advantage to using one in this application would be noise reduction, not water flow.

[Viggen]

I have done it before..... 

[slandis3]

remember if your running any size overflow at max and something goes wrong, its goina make a mess twice as fast if your only running it at half flow. Im starting to like the idea of running slow flow through my sump and return lines and rely on powerheads, wavemakers, and/or closed loops to handle the monster flow in my tank (not that i have a huge amount of flow yet). I would go with the 1" pipe get a 500gph-600gph return pump and some powerheads.

[Secondgen]

Thanks for the suggestions guys. Joel I don't know if you remember this tank or not, but I don't think I will be able to fit a durso style standpipe inside of the overflow. What I did have in mind after everyone's input is a 1" T fitting right off the bulkhead with a standpipe going up with a cap to let the air escape. As for the downward send, I will have the drain T off into two 1" pipes with valves, one to the fuge, and one to the skimmer section. Have I forgotten anything? I am using a 20 long that I made into a sump. I have the skimmer in the first chamber, the return pump in the center chamber, with the fuge in the final chamber. Let me know what everybody thinks. I do appreciate the feedback.

[Joel]

Gary, your nutts. I believe that you believe that you have pushed 1000 Gph thru a 1 " drain  but it's not physically possible. Once you hit 600-ish GPH, a 1" drain gets really noisy and often can't keep up. This is especially true if the plumbing after the 1" drain is not a straight shot to the sump.

Dave, I don't understand the reason for the "t"  / stand pipe with a cap in the o/f box. What are the advantages of this?

[Secondgen]

The T / cap will be on the outside of the tank to let the air escape from the overflow pipe as the water is sent down to the sump, and thus make it quieter.

[Joel]

The T / cap will be on the outside of the tank to let the air escape from the overflow pipe as the water is sent down to the sump, and thus make it quieter.

Ah, I got ya. I thought you were putting the "t" inside the o/f box. Yes that can work, just make the stand pipe as tall as the water level in the tank and don't completly cap it off, leave it open or drill a hole in the cap. I actually don't cap vent line like that, I 90 degree the top of it back into the tank or overflow bos so if there ever is a "blurp" up it, it will go back into the tank.

[Secondgen]

Thats a great idea Joel, I will definitly implement that. Thanks for the tip.

[Viggen]

Oops... didn't realize I posted that last one.... I didn't mean to, had to work

Anyways, I had a 1 in drain on a external overflow box on a 150g tank powered by a Velocity T4 pump.   At least I think that pump would flow about 1000 gph, same pumps I use now on both of my tanks.  However I do have bigger drains in these....