Return Pipe Fine or Fail?

[cilyjr]

It seems obvious to me that the return from the sump water to the tank will be contributing somewhat to the overall flow. That said when considering return pump I would not factor in water movement in the display.

The factors I look at are Sump flow (if that's important) and the equipment it will run (ie. If one runs a manifold). Impeller driven/ centerfugal pumps are not as effective for broad water movement.

That said disperse the return flow through the display however you like. But unless it's a large pump or have placed restrictions on the outlets, the the later outlets will be less effective

 

[HardCory]

It seems obvious to me that the return from the sump water to the tank will be contributing somewhat to the overall flow. That said when considering return pump I would not factor in water movement in the display.

The factors I look at are Sump flow (if that's important) and the equipment it will run (ie. If one runs a manifold). Impeller driven/ centerfugal pumps are not as effective for broad water movement.

That said disperse the return flow through the display however you like. But unless it's a large pump or have placed restrictions on the outlets, the the later outlets will be less effective

Hmm. Definitely something to consider. Thanks for the info!

 

[ReeferBob]

It seems obvious to me that the return from the sump water to the tank will be contributing somewhat to the overall flow. That said when considering return pump I would not factor in water movement in the display.

The factors I look at are Sump flow (if that's important) and the equipment it will run (ie. If one runs a manifold). Impeller driven/ centerfugal pumps are not as effective for broad water movement.

That said disperse the return flow through the display however you like. But unless it's a large pump or have placed restrictions on the outlets, the the later outlets will be less effective

Sizing a return pump is dependent mostly on the rate that your DT drains water to the sump. To a secondary amount anything that you might run as an accessory within the sump. DT Water movement is not factored into the return pump not because one doesn't want the return pump to be the primary source of water movement but because it has no bearing on it. DT return water is purely a function of what your drains will flow. DT Water circulation does not add nor take away from return water.

All situations are different. In mine, I am running 2 full siphons (1 in each megaflow). Feeding 2 full-siphons (~1200gph) requires enough water to create a lot of flow in the DT using just the return water. In my case I could remove my propeller pumps and still have plenty of water movement using just the return water. A lot of tank advice you hear is outdated. Certainly this one came about before the proliferation of the full-siphon drain. A lot of it is also money driven especially by companies that make $700 propeller pumps. ;)

If one was running a durso that would be considerably less water and probably not enough to depend on it alone for DT water flow. I'd present a strong argument that if you are returning anywhere over 1000gph to the DT you have enough return water to rely solely on that return water to circulate your DT and do not need a propeller pump.

 

[HardCory]

Hey guys, so I figured I'd do my best to do trial run with the return as is. The pump I had on hand is, I believe, a mag 5. So it's under powered but I at lest figured I could get a rough idea.
Sure enough, most of the flow came out one side while the other side...not so much. Here's the strange part...
The heavy side was the second outlet in the far end. The weak was the first.
Unless I misunderstood, I thought it would've been reversed...
Either way, this does make me sad. If it would've been 60/40, maybe even 70/30, I would've been ok with it. But this is 90/10.
I'm sure the correct pump would change the results but I think I just have to redo it and T it off...*sigh*

 

[ReeferBob]

Hey guys, so I figured I'd do my best to do trial run with the return as is. The pump I had on hand is, I believe, a mag 5. So it's under powered but I at lest figured I could get a rough idea.
Sure enough, most of the flow came out one side while the other side...not so much. Here's the strange part...
The heavy side was the second outlet in the far end. The weak was the first.
Unless I misunderstood, I thought it would've been reversed...
Either way, this does make me sad. If it would've been 60/40, maybe even 70/30, I would've been ok with it. But this is 90/10.
I'm sure the correct pump would change the results but I think I just have to redo it and T it off...*sigh*

You could put a ball valve on the line and crank it back. Not surprising the water rushes into the nice straight run to the end.

 

[HardCory]

You could put a ball valve on the line and crank it back. Not surprising the water rushes into the nice straight run to the end.

Yeah. As I was typing, it made sense on why it would be at the far end.
Unfortunately, putting a ball valve would be too much of an eyesore. If have to splice it in so it would be sitting inside the display. That's too much, even for me. I'll just have to redo the whole thing. Not a big deal, just a pain.

And a little disheartening

 

[ReeferBob]

Yeah. As I was typing, it made sense on why it would be at the far end.
Unfortunately, putting a ball valve would be too much of an eyesore. If have to splice it in so it would be sitting inside the display. That's too much, even for me. I'll just have to redo the whole thing. Not a big deal, just a pain.

And a little disheartening

One other option is to put a size-down bushing on the last outlet. Then of course you'd have to size it back up to fit your existing loc-line or else get the next smaller loc-line fitting.

 

[HardCory]

One other option is to put a size-down bushing on the last outlet. Then of course you'd have to size it back up to fit your existing loc-line or else get the next smaller loc-line fitting.

Thanks for the ideas, but I think I'm just gonna bite the bullet and do it the "right"way haha. I'll be ok...don't you worry about me! ...I'll be fine! *sniff*[emoji22]

 

[cilyjr]

Hmmm. A mag 5 at 5 feet head is only about 250gph. Sorry it didn't work out for you.

@ReeferBob I guess we will have to agree to disagree. I think there's A lot more to prop driven pumps for water movement. But I'd rather not derail hardcory's thread further.

 

[Stugots]

Reading with interest. I think you all make some good points. Hardcory, I think you'll be a lot happier when you get this done outside the tank as much as possible, and with a more powerful pump.

 

[HardCory]

Reading with interest. I think you all make some good points. Hardcory, I think you'll be a lot happier when you get this done outside the tank as much as possible, and with a more powerful pump.

Yeah. The pump that will be used is...currently in use in my current tank haha. Bigger DC pump.
I'll be working on the PVC sometime this week. Get it done right!

 

[ReeferBob]

Once you lose an anemone to a propeller pump you also may change your mind a bit about them. There is something to be said for a DT circulation system that only has an output! Further, the only devices I have ever had fail are propeller pumps. And they fail a lot. More than one has leaked electricity into the water.

 

[cobast]

Hey Harcopy, hydraulics and fluidics are strange. They seldom do what you expect. You should only use restrictions and valves to distribute your flow as a last resort. This is because you are using restrictions to reduce your flow and hence efficiency of your water flow. You are much better off designing your manifold properly in the first place. As has been suggested, put your manifold on the back of the tank a use a Y fitting (if you can find one) to split the return tubes. A Y fitting will flow better than a T fitting. Have the two tubes of equal lengths and with as few turns etc as possible as they go into the tank. You could even go to a slightly smaller tube after the Y splitter to keep your flow rate up. If you keep the same size throughout, your flow rate will drop after the split so you will lose some of the circulation effect of the returns.
I imagine the reason your set up test surprised you with more flow coming from the far outlet is because the water at the first outlet had high velocity and inertia and just flowed straight past the outlet = path of least resistance. When it reached the far end there would be massive turbulence and back pressure/ back flow so the water would pour out that outlet. That back pressure would build up somewhat back to the first outlet for a lesser flow.
I'll shut up now.
Good luck with your new manifold!

 

[Ubergroover]

Hey Harcopy, hydraulics and fluidics are strange. They seldom do what you expect. You should only use restrictions and valves to distribute your flow as a last resort. This is because you are using restrictions to reduce your flow and hence efficiency of your water flow. You are much better off designing your manifold properly in the first place. As has been suggested, put your manifold on the back of the tank a use a Y fitting (if you can find one) to split the return tubes. A Y fitting will flow better than a T fitting. Have the two tubes of equal lengths and with as few turns etc as possible as they go into the tank. You could even go to a slightly smaller tube after the Y splitter to keep your flow rate up. If you keep the same size throughout, your flow rate will drop after the split so you will lose some of the circulation effect of the returns.
I imagine the reason your set up test surprised you with more flow coming from the far outlet is because the water at the first outlet had high velocity and inertia and just flowed straight past the outlet = path of least resistance. When it reached the far end there would be massive turbulence and back pressure/ back flow so the water would pour out that outlet. That back pressure would build up somewhat back to the first outlet for a lesser flow.
I'll shut up now.
Good luck with your new manifold!

Beat me to it..

 

[Engloid]

Sizing a return pump is dependent mostly on the rate that your DT drains water to the sump.

It should return to the sump at the same rate that it's pumped to the tank. :)