Silent and Failsafe Overflow System

Please indulge me. My tank is only small so space is at a premium. Trying to get this box small as possible is important. Please explain if you would why this wouldn't work, and do the rest of the dimensions sound ok.

Many thanks.
 
Friction losses, with water moving into the pipe, through a relatively small opening.

The dimensions you have provided don't tell me anything about the setup at all, other than relative positions. Read back several pages and look for the dimensions that are posted, as being critical, and we can go from there. Usually, when someone gets more concerned about making things as small as possible, rather than putting function first, they end up with a system that won't work as intended, because the critical dimensions are wrong. :)
 
Bush off the pump directly to 1". Don't pass go, do not collect two hundred dollars on the way... ;)

I had read someplace that going larger on the output size is asking for cavitation problems with pumps. Don't know where I read that or if I even got it right. I do notice that seems like intakes are always bigger then outputs on pumps. And great googly moogly will someone please take a gander at my "coast to coast" idea in http://www.reefcentral.com/forums/showthread.php?t=2429236 Please :wildone:
 
I had read someplace that going larger on the output size is asking for cavitation problems with pumps. Don't know where I read that or if I even got it right. I do notice that seems like intakes are always bigger then outputs on pumps. And great googly moogly will someone please take a gander at my "coast to coast" idea in http://www.reefcentral.com/forums/showthread.php?t=2429236 Please :wildone:

It depends on the type of pump, and the size of the inlet.

For external pumps, you do not want to increase the outlet pipe size larger than the intake pipe size. Doing so will cause the pump to cavitate. (pressure differentials.) But it is really easy to deal with this. Example: 3/4 inlet and outlet. We know that performance of the pump will increase, by increasing the outlet plumbing to 1". (Fluid Dynamics.) But this presents a dilema, a problem.

The inlet/outlet size does not determine the size of the plumbing needed for a given pump in a given system. Flow rate and friction loss do. (keeping it simple, but variables such as distance to the intake volute from the source is also involved; lifting water e.g. pump higher than the water level in the source container as well, etc.) The way to solve the cavitation dilema, with our imaginary pump above, is to increase the intake plumbing size to 1". Larger outlet, larger inlet, a large as you care to go. With each pipe size increase, the actual output of the pump will increase, with the limitation of static head height on the flow curve, and an understanding that a plumbing system without friction loss does not exist.

Submersible pumps are a different story. Since there is seldom, if ever, plumbing attached to the pump intake, the outlet pipe size rule does not apply, as the actual intake volute for the pump will always be flooded. Example: Mag Drive pumps 9.5 and larger require 1.5" outlet pipe to get any flow out of them.

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I am certain that your 'overflow' design will get water out of the tank, but I think you need to work on it a bit more...without getting into the pertinent fluid dynamics, (things such as friction loss, single body of water vs hole in the side of an overflow) how you going to support that thing? I saw it a day or so ago, but the amount of typing would give me a headache... ;) Look into such endeavors as bridging dual corner overflows, (a related topic) vs complete removal of corner overflows and replacing with much better designs....
 
thank you uncle for the suggestion i will use 1.25 inch for the plumbing then unless you see any benefit with me using 1.5 inch other than i have some laying around = cost savings is all?
 
Example: Mag Drive pumps 9.5 and larger require 1.5" outlet pipe to get any flow out of them.

Now this I do not believe to be correct at all...

I am no expert at all but the larger the outlet plumbing, the more dramatic the head pressure becomes...

A pump would have to push up twice as much "water weight" with 1.5" plumbing than it would with 3/4" plumbing... You have twice the water weight, moving slower...
 
Now this I do not believe to be correct at all...

I am no expert at all but the larger the outlet plumbing, the more dramatic the head pressure becomes...

A pump would have to push up twice as much "water weight" with 1.5" plumbing than it would with 3/4" plumbing... You have twice the water weight, moving slower...

:) With some things, it is far wiser to believe, than to not believe. However, when there is a natural science behind it, belief is not necessary. But yes, in a way you should not: 1.5" is the minimum size... ;) I had never heard of such a thing, (such a large increase in pipe size being needed,) till it was put rather bluntly to me. I had always indicated it was prudent to increase the pipe size by one size. The mag drives are particuarly poorly engineered pumps...the flow increase is along the lines of several hundred gph.

I direct you to the Danner Mag 9.5 instructions, page 2 just below the bar graph:

http://www.dannermfg.com/Store/images/instructions/ZG100.pdf


Pressure and weight are not the same thing. Weight involves mass and the acceleration due to gravity, it is static, at rest. Water is a liquid, pressure is static or dynamic (in motion,) and though it does have mass, and is affected by acceleration due to gravity, that has nothing to do with head pressure. Folks very often get weight and pressure mixed up.

We have a 1" pipe, 100' tall. Filled all the way to the top with water. The pressure at the bottom of the pipe, (head pressure) is x. We move to the ocean, we go down 100', and we find that the pressure at that point is also x. Pressure at a given depth in a volumes of water, is equal, and it is equal in all directions, regardless of the size of the container, Not accounting for local ambient pressure. (Barometric pressure.) Though the weight of water in the ocean is far greater than the weight in our 1" pipe, at the same depth the pressure will be equal.

So from this, it can be seen that weight is not a factor (e.g. how much does the water in the pipe weigh.) Having a pump push water up 100' in 1" pipe, the pump will see the exact same head pressure as it would in the middle of the ocean at the same depth. However, the output of the pump will be greater in the open ocean, than it will be in the 1" pipe. The reason is friction loss, or loss in pressure due to being in contact with the pipe walls, in the 1" pipe. There are several terms for pressure in fluid dynamics, but none of them are related to weight.

Since this is dynamic, the natural science of this topic is called fluid dynamics, a subdiscipline of fluid mechanics, (deals with fluid flow) the natural science of liquids and gases in motion. More specifically it is Hydrodynamics...seperates it from Aerodynamics.

We are getting pretty far away from the topic in this thread, however, fluid dynamics is important in drain systems, as well as return systems.
 
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Now this I do not believe to be correct at all...

I am no expert at all but the larger the outlet plumbing, the more dramatic the head pressure becomes...

A pump would have to push up twice as much "water weight" with 1.5" plumbing than it would with 3/4" plumbing... You have twice the water weight, moving slower...

This is a very common perception, but wholly incorrect. The pump does not see or understand the "weight" of the water column against it. The pump sees pressure differential between the suction (inlet) and discharge (output) side.

The pressure at the bottom of a 10 foot tall drinking straw is the same as the pressure at the bottom of a 10 foot swimming pool is the same as the pressure measured 10 feet deep in the worlds largest ocean.
 
I had read someplace that going larger on the output size is asking for cavitation problems with pumps. Don't know where I read that or if I even got it right. I do notice that seems like intakes are always bigger then outputs on pumps.

Increasing the diameter of the discharge piping can only create cavitation if the suction side of the pump is restricting the ability of the pump to intake the amount of water it is capable of pumping.

If the suction piping is properly sized, then the pump will NOT cavitate. regardless of the size of the discharge plumbing.

It follows that if one restricts the suction side of the pump, then the discharge side must also be restricted to compensate for the lower pumping capacity, as otherwise the pump will cavitate.


As for you split PVC overflow... many folks have fiddled with setups like that but they never work out well. Ignoring the fabrication and placement issues, the "slot" becomes easily overwhelmed by water.
 
As for you split PVC overflow... many folks have fiddled with setups like that but they never work out well. Ignoring the fabrication and placement issues, the "slot" becomes easily overwhelmed by water.

I can't believe I'm about to say this to "THE BE AN ANIMAL" but, I'm going to try and overwhelm a PVC in the near future! I'll post on how it works out for me :)

ref http://www.reefcentral.com/forums/showthread.php?t=2429236
in case anyone wondering
 
I can't believe I'm about to say this to "THE BE AN ANIMAL" but, I'm going to try and overwhelm a PVC in the near future! I'll post on how it works out for me :)

ref http://www.reefcentral.com/forums/showthread.php?t=2429236
in case anyone wondering

Feel free to experiment with whatever you please :)


The slotted PVC pipe overflow has been around for quite some time and may work ok depending on the flow rate. If you search around you should find a few threads with photos (and maybe a video or two).

Have fun :)
 
what design do people prefer? an internal box leading to an external box with the plumbing? Or just plumbing it directly to the internal?

With the direct to internal, it would be 3 1" bulkheads into 1.5" pvc.

Internal skimmer to the external box via 2 2" holes, with the external being plumbed by 3 1" bulkheads, into 1.5" PVC.

The return is going to be 1", though I'm not sure if I'm going to split it off, or just use the 1 return.
 
what design do people prefer? an internal box leading to an external box with the plumbing? Or just plumbing it directly to the internal?

With the direct to internal, it would be 3 1" bulkheads into 1.5" pvc.

Internal skimmer to the external box via 2 2" holes, with the external being plumbed by 3 1" bulkheads, into 1.5" PVC.

The return is going to be 1", though I'm not sure if I'm going to split it off, or just use the 1 return.

This would be a difficult question to give a reasonable answer to. Though many repetitive questions are asked about an internal/external setup, how many actually get built, is hard to say. I built one internal/external (one of many systems) and if I had to do it over again, I probably wouldn't. I don't think it was worth the extra work...even though I was able to get more money out of it.

I think that any popularity it does have, is based on folks being enthralled with the notion of a mini-footprint inside the tank, but I don't find that a good enough reason, considering I have been there done that...and many seem to be getting carried away with it. The holes have to be x inches down from the top of the tank/glass, and only the bottom half of the hole used, so the height savings may be an inch if that...front to back you need enough room so the water fall does not hit the back wall of the tank, depending on flow rate, you many save an inch or two front to back...hardly worth getting excited about really.

The biggest improvement is changing from corner overflows to the C2C, and beyond that is mostly imagined improvement. If you want to do an internal/external, hey go for it; I have a template posted in this thread somewhere. I would not do it because it appears to be popular however, as being popular is quite often not for a good eonough reason...
 
thanks bud.

I'm definitely doing the bean, and I'm being convinced to just plumb it directly to the tank wall.

Next question I have would be whether I should split the return into 2 lines, or just have a single 1" return? or would that depend on what pump I got?
 
I have just acquired a DSA 110g tank that has a center overflow with 4 holes. 2 for 3/4" and 2 for 1".

My thinking is to use 1" for the emergency and partial siphon lines and a 3/4" for the full siphon line. What size pipe should I use either side of the bulkheads? Up 1/4"? 1/2"?

This leaves a 3/4" that I could cap or use for return. Return pump is an eheim 1262 (~600gph with head, currently on my 90g) or a Water Blaster HY-7000 (~900gph w/head) mostly depending on noise probably.

I suspect I will split the return line over the back even if I use the hole in the box, perhaps the extra space could allow larger pipes for the drains.

Thanks in advance.
 
thanks bud.

I'm definitely doing the bean, and I'm being convinced to just plumb it directly to the tank wall.

Next question I have would be whether I should split the return into 2 lines, or just have a single 1" return? or would that depend on what pump I got?

Power head primary function is to distribute returned water to all points of the tank, eliminating dead spots. At some point, considering tank size, multiple return outlets would be helpful, but with most common tank sizes, the reduction in flow rate caused by the addtional friction loss in the plumbing, makes it a toss up. I suppose it is sorta a matter of the pump: do you want to do the job efficiently, or oversize the pump, to do the same job. I put up a 325 with a single return, granted it is a 2" return, with ~ 3 grand flowing, and 4 vortecs in opposition...
 
Power head primary function is to distribute returned water to all points of the tank, eliminating dead spots. At some point, considering tank size, multiple return outlets would be helpful, but with most common tank sizes, the reduction in flow rate caused by the addtional friction loss in the plumbing, makes it a toss up. I suppose it is sorta a matter of the pump: do you want to do the job efficiently, or oversize the pump, to do the same job. I put up a 325 with a single return, granted it is a 2" return, with ~ 3 grand flowing, and 4 vortecs in opposition...

Was planning 1" return, eheim 5000 pump...I'm going to be putting in 1 or 2 Koralia pumps.

tank is planning to be a 110 gallon (60x18x23) FOWLR.
 
I have just acquired a DSA 110g tank that has a center overflow with 4 holes. 2 for 3/4" and 2 for 1".

My thinking is to use 1" for the emergency and partial siphon lines and a 3/4" for the full siphon line. What size pipe should I use either side of the bulkheads? Up 1/4"? 1/2"?

This leaves a 3/4" that I could cap or use for return. Return pump is an eheim 1262 (~600gph with head, currently on my 90g) or a Water Blaster HY-7000 (~900gph w/head) mostly depending on noise probably.

I suspect I will split the return line over the back even if I use the hole in the box, perhaps the extra space could allow larger pipes for the drains.

Thanks in advance.

1.25" for the open channel, easier to keep it quiet. 1" for the dry emergency is fine. The bottle neck is the siphon, with a 24" drop, the max theoretical flow capacity for a 3/4" bulkhead is 938gph, not accounting for friction loss, ambient pressure, blah blah, without any pipe attached.

Assuming your estimated flows per pump are accurate, (they probably aren't, due to friction loss) you would have an issue using the water blaster, with any size pipe, and a 3/4" bulkhead—assuming only a 24" drop. Real world, considering you mention using a 3/4" bulkhead for return and/or splitting the return, your pumps will not be operating close to the flow curve, so I don't see 1" pipe on the 3/4" bulkhead for the siphon, causing a problem. I would not consider using 3/4" pipe useful.

Whether or not either of those pumps is useful for a tank this size, is a seperate question, but I would want to run it up around 1000gph after accounting for the total dynamic head, relegating both those pumps to trash heap, I don't have the specs on the water blaster handy though... ;)
 
Was planning 1" return, eheim 5000 pump...I'm going to be putting in 1 or 2 Koralia pumps.

tank is planning to be a 110 gallon (60x18x23) FOWLR.

This is exactly what I was getting at. These tanks have a small surface area for the depth, and they do not breath well. (gas exchange) which increases the burden on the recirculation (in/out) volume, which is why they are not the 'best' for marine systems. You will probably need both power heads if not some added umph as well. But, we are getting pretty far away from the topic of the drain system.

Also, you want an 1.25" return line, to reduce the friction losses, for that pump.
 
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