Overflow Drain Pipesize?

Mywifeisgunnakillme · Feb 14, 2021

Hey I have a 200 gallon innovative marine and need to buy hard and soft piping. The overflow comes with 1 inch drains. I did have the sump made to have 1 inch connections. The distance between the overflow and sump can be 4 to about 15 feet depending on how i place the sump in the sump room.

Question, one inch pipe fine no matter what? Or should i use 1.5 inch pipe in any case?

Benefits to different size pipe? Drawbacks?

The returns (two) on the tank are 3/4 inch. I had 1 inch connection made on the sump (two). I have two (eheim) return pumps (each probably about 700 to 900 GPH). One will go to a manifold that may run other equipment as well as the tank.

Thanks!

Idoc · Feb 14, 2021

If your tank is drilled for 1" bulkheads for 1" pipe as well as 1" connections on your sump, then that is the bottleneck. No matter how big of PVC you use between the bulkhead and the sump connection, you are still only going to get 1" max of water going through those pipes. So, 1" PVC piping should be sufficient for the drains.

Mywifeisgunnakillme · Feb 14, 2021

Idoc said:
If your tank is drilled for 1" bulkheads for 1" pipe as well as 1" connections on your sump, then that is the bottleneck. No matter how big of PVC you use between the bulkhead and the sump connection, you are still only going to get 1" max of water going through those pipes. So, 1" PVC piping should be sufficient for the drains.

Well, that's no very true. While the very short (less than 1 inch) length's of connections at the overflow and at the sumps do provide some restriction--those connections basically add zero total restriction if you run larger pipe the rest of the pipe run...

This reality may not be obvious at first. But if you think about it--it's very true. For example, as a former craft brewer, i use to run draft beer lines all of the time. The key to draft beer lines (the same thing basically as sump lines, i.e., moving liquid from one place to another and figuring out the volume you want to move), is you want a slow flow at the tap, but enough flow to push the beer from the keg to tap.

Leaving aside the math calculations, google them if you want, stated simply flow rates are determined by overall restriction and restriction is calculated by the diameter of the pipe relative to its length.

A few inches of 1 inch restriction (at the overflow and at the sump connections) is totally inconsequential to determining the flow rate if the remaining 4 to 15 feet of tubing/pipe is 1.5 inches in diameter; the flow rate will be basically the same as if the connections at the sump and return are 1.5 inches...

Anyway, for the purpose of my question, just ignore the connection sizes at the sump and overflow because they basically do not add any total flow restriction... (15 feet of 1.5 inch tubing could be say, making this up as an example, have a flow rate of 1000 gallons an hour. If you add 1 inch restrictions on both ends, with a length of only 3 inches, say, the flow rate would be 975 gallons an hour.... Where as15 feet of 1 inch pipe the whole way would have flow of say, comparatively, 730 gallons any hour...)

What size pipe do i want for 4 to 15 feet of overflowing piping given i have 2 eheim return pumps each 700 to 900gph?

Thanks!

Saltyreef · Feb 14, 2021

Mywifeisgunnakillme said:
Well, that's no very true. While the very short (less than 1 inch) length's of connections at the overflow and at the sumps do provide some restriction--those connections basically add zero total restriction if you run larger pipe the rest of the pipe run...

This reality may not be obvious at first. But if you think about it--it's very true. For example, as a former craft brewer, i use to run draft beer lines all of the time. The key to draft beer lines (the same thing basically as sump lines, i.e., moving liquid from one place to another and figuring out the volume you want to move), is you want a slow flow at the tap, but enough flow to push the beer from the keg to tap.

Leaving aside the math calculations, google them if you want, stated simply flow rates are determined by overall restriction and restriction is calculated by the diameter of the pipe relative to its length.

A few inches of 1 inch restriction (at the overflow and at the sump connections) is totally inconsequential to determining the flow rate if the remaining 4 to 15 feet of tubing/pipe is 1.5 inches in diameter; the flow rate will be basically the same as if the connections at the sump and return are 1.5 inches...

Anyway, for the purpose of my question, just ignore the connection because they basically do not add any flow restriction...

What size pipe do i want for 4 to 15 feet of overflowing piping given i have 2 eheim return pumps each 700 to 900gph?

Thanks!

Sounds to me you already know the answer to the question.
Id stay with 1" as you dont need 1.5 for that amount of flow or turn over.
Also simplifies things.....

BlennyTime · Feb 14, 2021

If you have 3/4” return pipes, then 1” drain pipe is fine.

Mywifeisgunnakillme · Feb 14, 2021

Saltyreef said:
Sounds to me you already know the answer to the question.
Id stay with 1" as you dont need 1.5 for that amount of flow or turn over.
Also simplifies things.....

Well, no i don't know the answer. That is why i am asking. I have no idea whether i should run 1.5 or 1 inch pipe? I have no idea what max flow rates are for each size pipe over a given length of pipe...

What size pipe are people using for 4 feet to 15 feet runs is my question?

Is 1 inch pipe sufficient for the overflow pipe given i push 1400 to 11800 gallons back to the tank?

Is one size more quiet than another?

Does one size do better for other reasons?

To be clear, i don't really care about the math (lots of combo's likely work) i more care about what people are using and their experience if similar to what i am proposing?