Questions about Overflow/Return pump GPH

[JNalley]

I think I am going to drill my tank and add a sump. Probably going to use some sort of internal/external overflow like the FijiCube or the Eclipse. I like the sound of a bean animal for the redundancy (I know, most people say it's unnecessary, but more safety is preferable), however all of the bean animal style overflows I'm looking at are like 1,000 GPH or more, I understand tuning it with a gate or ball valve, but my question is more to do with how far can we reduce the flow before the velocity is slowed enough that the siphon doesn't work? I'm going to be doing this on a 32.5 gallon tank into a 20 gallon long sump. I probably only need about 150 - 300GPH of flow for a setup of this size, so will an overflow rated at 1,000 GPH even work correctly at 150-300 GPH?

 

[JumboShrimp]

I would say use 2 street 45s instead of 1 90-degree elbow on the pipes coming down from your overflow and gravity will do the rest, even if you have to close your valves significantly.

 

[WVNed]

A drilled tank doesn't use a siphon.

 

[Gtinnel]

A drilled tank doesn't use a siphon.

The main drain on a bean animal drain setup is often called a siphon.

 

[WVNed]

Hot dogs aren't dogs at all

 

[Gtinnel]

Hot dogs aren't dogs at all

Hey I don't make the names. I have no clue why it gets called a siphon since the definition of siphon involves water going upwards.

I did have to look up the definition of siphon to be sure that was the actual definition though.

 

[WVNed]

A HOB overflow uses a siphon to get water over the side of the tank. If it flows to slow it will accumulate air at the top of the tube and fail.

A drilled tank doesnt have a siphon because it doesn't need to lift water over the tank edge, all it has are drains with water flowing down. These cannot fail unless they get plugged.
They can get plugged with nothing more than air. The way to prevent that is to size your drain pipes according to your flow. Small flow stick to 3/4 inch drains.

 

[JNalley]

because of the 180 degree bend in the pipe it is a siphon, water goes upwards then sideways, then down... See diagram:

 

[Gtinnel]

As for the original question, I'm no expert on that type of drain setup (or any drain setup) but I don't see why it wouldn’t work at a much lower flow rate. Like mentioned you would just have to close off the gate valve significantly.

 

[WVNed]

The main drain on a bean animal drain setup is often called a siphon.

Hey I don't make the names. I have no clue why it gets called a siphon since the definition of siphon involves water going upwards.

I did have to look up the definition of siphon to be sure that was the actual definition though.

Sorry in terms of his question I had to get technical. I generally use the term full siphon drain myself but that didnt seem to work in this case.

 

[JNalley]

Having had time to think about it though, since it's submerged, it's constantly being fed pressure, so I'm guessing the flow doesn't matter as much since there's also pressure

 

[WVNed]

because of the 180 degree bend in the pipe it is a siphon, water goes upwards then sideways, then down... See diagram:

No it isnt. That's why the top is vented.

 

[JNalley]

No it isnt. That's why the top is vented.

the top of the main siphon is NOT vented, the top of the open channel is vented...

 

[WVNed]

the top of the main siphon is NOT vented, the top of the open channel is vented...

I am curious. DId you build that and did it work?

 

[Gtinnel]

because of the 180 degree bend in the pipe it is a siphon, water goes upwards then sideways, then down... See diagram:

If that's the logic then why doesn't the secondary standpipe, or a regular durso get called a siphon, the water has to flow up, over, and then down even if the pipe isn't completely filled with water on those?
I knew it was often called a siphon, but I agree with @WVNed that it is not actually a siphon in the traditional sense.

Sorry I didn't mean to derail your thread a little discussing the pointless naming of a pipe.

 

[JNalley]

I am curious. DId you build that and did it work?

I did not build it, this is how a Bean Animal is built... And they do work...

 

[JNalley]

If that's the logic then why doesn't the secondary standpipe, or a regular durso get called a siphon, the water has to flow up, over, and then down even if the pipe isn't completely filled with water on those?
I knew it was often called a siphon, but I agree with @WVNed that it is not actually a siphon in the traditional sense.

Sorry I didn't mean to derail your thread a little discussing the pointless naming of a pipe.

Because of the venting no suction is created that can pull water up using gravity as it can in the main drain/siphon. If the water level falls below the bottom of the horizontal section of the pipe, that drain ceases to function, the same cannot be said about the main drain/siphon, it will continue to suck water until it falls below the mouth of the pipe. At least that's my understanding of it.

 

[WVNed]

A pipe with a 90 on top will not start unless the depth in the box is great enough to finally push the air down unless you drill a whole in the top of it to let the air out when it starts. Or you will end up with a pipe that takes a while to completely purge the air out so it is hard to adjust.
This is critical with low flows.

 

[Gtinnel]

Because of the venting no suction is created that can pull water up using gravity as it can in the main drain/siphon. If the water level falls below the bottom of the horizontal section of the pipe, that drain ceases to function, the same cannot be said about the main drain/siphon, it will continue to suck water until it falls below the mouth of the pipe. At least that's my understanding of it.

I can see that logic.

 

[JNalley]

A pipe with a 90 on top will not start unless the depth in the box is great enough to finally push the air down unless you drill a whole in the top of it to let the air out when it starts. Or you will end up with a pipe that takes a while to completely purge the air out so it is hard to adjust.

Not sure what to tell you, Bean Animals work, there are thousands of them running just like the one in the drawing, and the main drain/siphon does not have a hole on the top of it.

Just some examples of working Bean Animal overflow/drains