What tank size to go with??

[DRteugelsi]

From what i am reading head height also needs to be taken into consideration.

beananimal posted this on a forum:
"Scolley,

Water flow...

Yes water is pulled by gravity. It (for our purposes) behaves like a solid when it is confined by a pipe, so the further it falls, the faster it falls. It pulls on the water above it as well. I will leave it to you to research if the "pull" is created by surface tension or displacement

In any case we use the basic Bernoulli equation to explain how much water falls how fast.

Lets take the 2" SCH80 Bulkhead with a 1.913 inch I.D. and 48" of head.

h = "height" and denotes the head (water height) above the hole.
g = "gravity" denotes the free fall of an object here on earth.. (32ft/sec)squared

So we find the velocity and then plug it into the basic formula:
Q = A * V

Lets do some math:
2" SCH#80 PVC pipe I.D. = 1.913 inches.

So:
h= 6" = 4'
A= 2.873" sq. = 0.01995' sq.
g= 32f/s sq.

Find the Velocity:
V = sqrt(2* 32f/s^2 * 4f) = 16f/s

Find the flow rate (Q):
Q= 0.01995f^2 * 16f/s = 0.3192 Cubic Feet per Second.

The Result:
0.3192 Cubic Feet per Second = 143.25 Gallons Per minute
143.25 Gallons per Minute = 8595 Gallons Per Hour.

Long drop, lots of pipe and fittings... lets say 7250 GPH

Now... the larger the drop, the more friction and turbulance affect the velocity and therefore, the overall flow. Also note that "terminal" velocity is reached much faster due to the friction and turbulance and that cavitation can occur if the pressure drop (caused by the water falling through the pipe) exceeds the surface tension of the water itself....


The bulk of the gas exchange can happen at the sump. The surface skimming is another story. While your idea of using the open channel as the surface skimmer is interesting, I don't thik it will provide enough surface skimming for a modest system. You may be able to increase the efficiency of the small surface skimmer by directing surface flow towards it with power heads or CL nozzles. Like anything else, there are certainly many ways to reach the same goal. Good luck with the project! "
(Hope i am not breaking any rules.)

So, the chart would have to be pretty accurate if you are judging by the middle number

 

[DRteugelsi]

Though i am not sure i am just basing this off of what i am reading. I know the overflow box i am looking at already comes standard with 1.5" bulkheads and plumbing. I am trying to do a little research of my own so, I can better understand this.

"Measure twice, cut once"

 

[jaws7777]

I can definitely agree that the gravity drain column leaves a bit of description to be desired. However, the second column I am most certain is for lines attached to pumps. Because it has (40-100psi) in the description, this clearly indicates that there is a pushing force in the line which is creating the pressure. If you were to put a gauge on your drain line, it probably wouldn’t register any pressure at all, or possibly a psi or two. However, it would be very far from the minimum stated on the chart, which is 40psi.

Again i disagree. You are simplifying it where i think the dynamics of water movememt are much more complicated. I just proved to you that pressure would affect gph with the denitrate filter.

From what i am reading head height also needs to be taken into consideration.

beananimal posted this on a forum:
"Scolley,

Water flow...

Yes water is pulled by gravity. It (for our purposes) behaves like a solid when it is confined by a pipe, so the further it falls, the faster it falls. It pulls on the water above it as well. I will leave it to you to research if the "pull" is created by surface tension or displacement

In any case we use the basic Bernoulli equation to explain how much water falls how fast.

Lets take the 2" SCH80 Bulkhead with a 1.913 inch I.D. and 48" of head.

h = "height" and denotes the head (water height) above the hole.
g = "gravity" denotes the free fall of an object here on earth.. (32ft/sec)squared

So we find the velocity and then plug it into the basic formula:
Q = A * V

Lets do some math:
2" SCH#80 PVC pipe I.D. = 1.913 inches.

So:
h= 6" = 4'
A= 2.873" sq. = 0.01995' sq.
g= 32f/s sq.

Find the Velocity:
V = sqrt(2* 32f/s^2 * 4f) = 16f/s

Find the flow rate (Q):
Q= 0.01995f^2 * 16f/s = 0.3192 Cubic Feet per Second.

The Result:
0.3192 Cubic Feet per Second = 143.25 Gallons Per minute
143.25 Gallons per Minute = 8595 Gallons Per Hour.

Long drop, lots of pipe and fittings... lets say 7250 GPH

Now... the larger the drop, the more friction and turbulance affect the velocity and therefore, the overall flow. Also note that "terminal" velocity is reached much faster due to the friction and turbulance and that cavitation can occur if the pressure drop (caused by the water falling through the pipe) exceeds the surface tension of the water itself....


The bulk of the gas exchange can happen at the sump. The surface skimming is another story. While your idea of using the open channel as the surface skimmer is interesting, I don't thik it will provide enough surface skimming for a modest system. You may be able to increase the efficiency of the small surface skimmer by directing surface flow towards it with power heads or CL nozzles. Like anything else, there are certainly many ways to reach the same goal. Good luck with the project! "
(Hope i am not breaking any rules.)

So, the chart would have to be pretty accurate if you are judging by the middle number

Bingo exactly !!! Many factors impact how water moves through these systems.

Look all i know is i can gaurantee you if you post this in the filtration section 100% of the experienced members are going to tell you size everything around what your E drain can handle do not go with 1 as it most likely will be insufficient.

beananimal is said to be the safest and herbie a close second.

I like how in bean animal not only do you have an E drain but you also have the open channel taking on a little water. Thats fool proof right there. I also heard that dialing in the gate is easier because the open channel takes on some water so the adjustments dont have to be soo fine and accurate

1 inch or 1.5 drains can be adjusted with your gate so either way your fine.

 

[DRteugelsi]

I am getting a lot of mixed signals from what i am researching but it does look like 2200gph is the consensus for 1" pipe.

It does make sense though i mean i could drain a 125 with a 3/8 garden house at full siphon in less than 20 minutes. but once again I'm still not 100% on all of this.

At any rate 1.5" drains will still be best for my application as it would allow me to not have to worry about my e drain so much and i would have to do any mods to fit the pipe. still not certain on the purpose of the air hose on the beananimal though

 

[Fish Tank Travis]

From what i am reading head height also needs to be taken into consideration.

beananimal posted this on a forum:
"Scolley,

Water flow...

Yes water is pulled by gravity. It (for our purposes) behaves like a solid when it is confined by a pipe, so the further it falls, the faster it falls. It pulls on the water above it as well. I will leave it to you to research if the "pull" is created by surface tension or displacement

In any case we use the basic Bernoulli equation to explain how much water falls how fast.

Lets take the 2" SCH80 Bulkhead with a 1.913 inch I.D. and 48" of head.

h = "height" and denotes the head (water height) above the hole.
g = "gravity" denotes the free fall of an object here on earth.. (32ft/sec)squared

So we find the velocity and then plug it into the basic formula:
Q = A * V

Lets do some math:
2" SCH#80 PVC pipe I.D. = 1.913 inches.

So:
h= 6" = 4'
A= 2.873" sq. = 0.01995' sq.
g= 32f/s sq.

Find the Velocity:
V = sqrt(2* 32f/s^2 * 4f) = 16f/s

Find the flow rate (Q):
Q= 0.01995f^2 * 16f/s = 0.3192 Cubic Feet per Second.

The Result:
0.3192 Cubic Feet per Second = 143.25 Gallons Per minute
143.25 Gallons per Minute = 8595 Gallons Per Hour.

Long drop, lots of pipe and fittings... lets say 7250 GPH

Now... the larger the drop, the more friction and turbulance affect the velocity and therefore, the overall flow. Also note that "terminal" velocity is reached much faster due to the friction and turbulance and that cavitation can occur if the pressure drop (caused by the water falling through the pipe) exceeds the surface tension of the water itself....


The bulk of the gas exchange can happen at the sump. The surface skimming is another story. While your idea of using the open channel as the surface skimmer is interesting, I don't thik it will provide enough surface skimming for a modest system. You may be able to increase the efficiency of the small surface skimmer by directing surface flow towards it with power heads or CL nozzles. Like anything else, there are certainly many ways to reach the same goal. Good luck with the project! "
(Hope i am not breaking any rules.)

So, the chart would have to be pretty accurate if you are judging by the middle number

Ok, when I look at this more like a physics/fluid dynamics problem, these numbers make a lot more sense. Thanks for posting this. When I do the math for a 1” line using this method, I come up with about 2300gph at 4ft. The one thing this method doesn’t take into consideration is the friction in the pipe. This will slow the flow considerably. To be on the safe side, I recommend to only expect about 75% of the full flow calculation, so 75% of the 2300, which is 1725gph. However, if it were me, I would cut that to 50%, just to be safe.

 

[DRteugelsi]

Ok, when I look at this more like a physics/fluid dynamics problem, these numbers make a lot more sense. Thanks for posting this. When I do the math for a 1” line using this method, I come up with about 2300gph at 4ft. The one thing this method doesn’t take into consideration is the friction in the pipe. This will slow the flow considerably. To be on the safe side, I recommend to only expect about 75% of the full flow calculation, so 75% of the 2300, which is 1725gph. However, if it were me, I would cut that to 50%, just to be safe.

Exactly, there are so many other factors to take into consideration like algae and waste build up. (ill probably just snake the pipes once every month or so) I think 1.5" will be sufficient for what i am aiming for and allow me to keep everything the same size.

 

[twentyleagues]

Exactly, there are so many other factors to take into consideration like algae and waste build up. (ill probably just snake the pipes once every month or so) I think 1.5" will be sufficient for what i am aiming for and allow me to keep everything the same size.

Yes just make this easier and go with the 1.5. Just don't base your flow off of the 1.5" chart. Because your e drain can't handle the flow amount that a full siphon can. The bean animal is kinda a mix between the herbie and durso. You have a full siphon and a open drain or a durso and then the 3rd is emergancy. So say you use two of these you could go with a pump or 2 with a combind output of 2800gph because the durso or the e drain can only handle 1400gph each. So if you wanted to live on the wild side you could double it because you have a durso and an e drain that can each handle 1400 gph. But that could potentially cause a flood. It shouldn't and it's your house so your call.
http://gmacreef.com/aquarium-overflows-durso-herbie-and-bean-setups/
Basic break down of how each one works. Super easy to understand.