Thanks uncle. The stand will be about 40" tall and the sump will have the drain-section's waterline at 15", so the fall will be 25" + the height of the BA standpipes inside the overflow + 1" depth into the water. I plan for the drain pipes to be vertical with no elbows and make a straight shot to the sump.
Silent and Failsafe Overflow System
- Thread starter JohnL
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uncleof6
Active member
@ 5x 1" bulkheads are fine. @ 1800gph + (where it should be and to do this system justice) 1.5" bulkheads. It appears that you are aware of the surface skimming/renewal efficiency you are sacrificing in doing a peninsula type tank, opposed to a traditional setup, e.g. short weir to flow rate, and the distance being ~6' rather than ~2' you need to pull from. That needs to be taken into consideration when setting up your power head circulation scheme.
Thanks Uncle. The plan for me going peninsula is to create a circular pattern of water flow wherein the returns force water down the overflow wall, then maybe pumps on either side of the overflow down low to push the returned water toward the opposite side where the gyre (or MP, etc.) is positioned up high to push the water back toward to overflow while disturbing the surface all the way back to a 'toothless' weir/overflow. I'm hoping that this eliminates as many dead spots as possible. My next question is how thin a sheet of water I can get over the smaller trapezoid-shaped weir while getting 1800 gph through the sump?
uncleof6
Active member
Well 1800gph wants to see ~27" worth of weir, minimum, so it really depends on how wide your tank is. I assume that a 180 is ~24" wide, and that is close. I have recently gone looking into some dimensions, and I am seeing a lot of funky dimensioned tanks, that don't lend themselves very well to marine system. Those being taller than they are wide.
Weir calcs I don't like to do very much, the information can be garnered on the internet, and will be fairly accurate as to how thick the layer of water over the weir is going to be, using the Francis formula, you rearrange the equation to solve for h, the head on the weir.
http://www.engineeringtoolbox.com/weirs-flow-rate-d_592.html
That said, you want the thinnest layer possible. On the end of the tank, that will be the full width of the tank, regardless of flow rate, it won't get any better than that.
I also withdraw my comments concerning the gyre, and hang my head in shame. I had seen those before, but the name wasn't clicking in my head. Does exactly what I was talking about.
Weir calcs I don't like to do very much, the information can be garnered on the internet, and will be fairly accurate as to how thick the layer of water over the weir is going to be, using the Francis formula, you rearrange the equation to solve for h, the head on the weir.
http://www.engineeringtoolbox.com/weirs-flow-rate-d_592.html
That said, you want the thinnest layer possible. On the end of the tank, that will be the full width of the tank, regardless of flow rate, it won't get any better than that.
I also withdraw my comments concerning the gyre, and hang my head in shame. I had seen those before, but the name wasn't clicking in my head. Does exactly what I was talking about.
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Thank you, and no worries about the gyre - just threw me off track for a bit. I will look into the Francis formula and see what I come up with.
The tank is planned as standard 72x24x24. Is there a benefit from dropping the height to 22" or 20"?
For the overflow, will I get any benefit by having the trapezoid shape? I'm guessing 6"-8" per side and 15"-16" across the front. That will give me 27" - 32" of total weir.
uncleof6
Active member
There is, but 24 x 24 is fine. The classic examples are the 120 and 180, (24 x 24) being the quintessential marine tanks. My 300s are 72 x 36 x 30. (Actually around 325.) The 8' 240 is some folks dream tank, but a 5' 240 is a better tank, that one could be chalked up to an opinion I suppose, as the 8' has more surface area, by 144in².
Starting at the 55 and going up through the sizes ending in 5 are more for freshwater systems, and are not well suited for marine systems. That is not an opinion, rather is based on the surface area to volume ratio, in terms of gas exchange.
The ends of the weir count, if it is a 3 sided type arrangement, or trapezoid configuration. It will get dicey the closer the weir comes to the glass, and water starts splashing off. Just don't short change your self in the plumbing room, 16" is pretty small. I think an L shaped shelf 24" wide will do the job, though a 72" weir would be much better...
Joe the painter
New member
hi everyone I am setting up a brand new 210 and i am new. I just drilled my holes for 1.5 bulkheads 4 inches from the top of the black trim to the top of the hole. i know i screwed up,but its too late. will the ba still work? if not is there anything i can do to correct the problem?
uncleof6
Active member
Of course it will work, you will just have a higher waterfall into the overflow, which may make some noise, and the box will have to be taller.
xtrattitude4u
New member
I have a 100 gallon tank with a built in overflow I am trying to modify for this system. The drain section is small, and I'm having to drill holes creatively to fit the siphon and open stand pipes in the overflow box.
Is there an issue with having the emergency pipe in the tank?
I know that it would only take on water if the dt water level rises, but I think it would still work if it had to. I'm wondering how it would affect the system at startup, possibly hindering the full siphon starting on the main pipe?
Thanks!
Is there an issue with having the emergency pipe in the tank?
I know that it would only take on water if the dt water level rises, but I think it would still work if it had to. I'm wondering how it would affect the system at startup, possibly hindering the full siphon starting on the main pipe?
Thanks!
uncleof6
Active member
There are no holes in the bottom of the overflow?
The BA does not lend itself well to small overflows such as this, and it is not recommended that you use it. The Herbie modification is better suited for it. (siphon and dry emergency.) You are pretty much stuck with that if the tank is acrylic, though these small overflows aren't sufficiently sized for the tank in the first place.
A better plan on a glass tank, is to remove the overflow, plug any existing holes, build a L shelf overflow at the top of the tank, drill out the back for a BA system.
The BA does not lend itself well to small overflows such as this, and it is not recommended that you use it. The Herbie modification is better suited for it. (siphon and dry emergency.) You are pretty much stuck with that if the tank is acrylic, though these small overflows aren't sufficiently sized for the tank in the first place.
A better plan on a glass tank, is to remove the overflow, plug any existing holes, build a L shelf overflow at the top of the tank, drill out the back for a BA system.
SARBoy
New member
Can I run a manifold off the siphon? I would ideally like to run my skimmers and other equipment/reactors from the return to sump line.
I would also run a submerged line into a filter sock from the manifold to keep the siphon quiet and dump any excess water into the sump not used by equipment.
Is this possible or does it need to be a straight shot to the sump from the overflow?
I would also run a submerged line into a filter sock from the manifold to keep the siphon quiet and dump any excess water into the sump not used by equipment.
Is this possible or does it need to be a straight shot to the sump from the overflow?
uncleof6
Active member
NO. It will mess with the operation of the system. Bad idea. Bite the bullet and do it right. Straight shot to the sump. Run the skimmer on its own pump, and run whatever else you feel you need from a tee in the return line. (The return goes from sump back to the tank. The line from the overflow to the sump is called a drain.
)Filter socks, and any form of mechanical filtration really do not have a place in marine systems. That is a carry over from freshwater systems, as what we are concerned with in marine systems, cannot be removed by mechanical filtration. (The skimmer is actually a mechanical process, however lets not confuse the issue.)
Send any "excess" water back up to the tank, via the return pump. That is where it is needed. Dumping water back into the sump is a huge waste. Though what you are saying is not all that clear.
SARBoy
New member
Cheers for the reply uncleof6,
Yup, I thought that might be the case. I was just trying to capture the waste/drain from the display straight to the skimmers so they get a straight shot at the dirty water.
Not much difference but the less pumps running the lower the cost of equipment, lecky, noise and things to go wrong.
I'm not sure I agree with the filter socks though. I've run a large system before and there is always some larger particles that a sock would be best at removing. You do have to keep on top of maintance as you don't want waste staying in the system. But it's either a case of siphoning them up or catching them in a sock.
Yup, I thought that might be the case. I was just trying to capture the waste/drain from the display straight to the skimmers so they get a straight shot at the dirty water.
Not much difference but the less pumps running the lower the cost of equipment, lecky, noise and things to go wrong.
I'm not sure I agree with the filter socks though. I've run a large system before and there is always some larger particles that a sock would be best at removing. You do have to keep on top of maintance as you don't want waste staying in the system. But it's either a case of siphoning them up or catching them in a sock.
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