Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
BeanAnimal
Premium Member
The physics are rather simple.
Put a straw into a glass and blow in it...
Now put a piece of tubing into your swimming pool and blow into into it...
The deeper the discharge, the more pressure it takes to purge the air from the system. If the air is not purged and the intake is submerged, then the standpipe fully (or partially) airlocks. In theory, the "safe" depth of the discharge would be "less" than the distance from the bottom of the intake elbow to the crest of its weir. In practice we can go a bit deeper
As you can see, each standpipe has a function and is an integral part of the overall system
rrasco
New member
I would put them all at 1 inch, but I think only the siphon and open channel need to be submerged since they are the ones that can be utilized as a siphon. The open channel converts to a full siphon as a 2nd fail safe to the emergency channel. However, thinking about it, I think if the water level was high enough in the overflow, the emergency channel may convert to a siphon while purging the overflow should it need to be used. To be safe, I'd go with all submerged.
uncleof6
Active member
Theoretical, and applied, none of them need to be submerged. This giving the least resistance to purging the air. Practicality wise, this would make for a noisy system--rather self defeating. With a need for the emergency to flow, it could be advantageous, as the noise could alert you to an issue with the drain system.
Another issue with starting, is caused by horizontal runs in the siphon line. Trapping air, and air locking.
joegoersch
New member
Yeah...that makes perfect sense, thanks ! I was confused, because the resistance to the flow of water should be independent of the depth of the discharge pipe, i.e. if you put the discharge pipe X inches deeper, you will get X extra inches of water pressure more at the bottom of the discharge pipe, so it's a wash...but of course, this doesn't hold for air in the pipe which has negligible density compared to water.
The distance from the top of the emergency standpipe on my system (which is just below top of weir) to the bottom of the intake elbow is about 3 inches and the depth of the discharge is only 1.5 inches, so I cannot explain how the 3 inches of water pressure was not able to overcome what should have only been 1.5 inches of water pressure resistance preventing purging of the air. In any case I'll cut an inch off the discharge line...
thanks again !
autodave
New member
I submerged all of mine less than 1 inch. Mine runs so quiet that any disturbance to the siphon,you will know something is not right.
Thank you Beananimal for your very clear, easy to follow instructions. It has been a blast putting this tank together with my son and this overflow was the centerpiece of our build.
I am pretty sure I have followed directions to the letter. I can not get full syphon on middle pipe. I seem to be getting more flow through the open pipe. But no where near full syphon through either. This is in a 40 breeder and using a Mag 7 return at I would say 4 1/2 feet heigth. Think that would equal out to about 400-420 gph. Is this too low of a flow rate for this system? I am using the exact pipe shown in the original illustration. Down to the VERY hard to get ahold of 1 inch - 1.5 elbow in the coast to coast overflow.
All drains terminate 3/4 to 1 inch under water level. Any help would be greatly appreciated.
Thanks again. (especially for help in getting a 16 year old away from his I-pad) :love1:
I am pretty sure I have followed directions to the letter. I can not get full syphon on middle pipe. I seem to be getting more flow through the open pipe. But no where near full syphon through either. This is in a 40 breeder and using a Mag 7 return at I would say 4 1/2 feet heigth. Think that would equal out to about 400-420 gph. Is this too low of a flow rate for this system? I am using the exact pipe shown in the original illustration. Down to the VERY hard to get ahold of 1 inch - 1.5 elbow in the coast to coast overflow.
All drains terminate 3/4 to 1 inch under water level. Any help would be greatly appreciated.
Thanks again. (especially for help in getting a 16 year old away from his I-pad) :love1:
Firochromis
New member
Hi people, I need help on selecting a pump output for my drain size.
I want to use a Red Dragon 6500 in my 120 g tank. My tank is 5 feet high from sump so it pumps some 1300 g to that height. I bought my tank second hand and previous owner drilled only one drain and it is 1.5". Return line is 3/4". According to calculator below, 1.5" is the minimum size for 1300 g. It also suggests 20" linear overflow size. I have 25" but it has grids, so roughly half of the length is blocked. According to this values, do you think ı should opt for a smaller pump?
http://www.reefcentral.com/index.php...flow-size-calc
Regards
I want to use a Red Dragon 6500 in my 120 g tank. My tank is 5 feet high from sump so it pumps some 1300 g to that height. I bought my tank second hand and previous owner drilled only one drain and it is 1.5". Return line is 3/4". According to calculator below, 1.5" is the minimum size for 1300 g. It also suggests 20" linear overflow size. I have 25" but it has grids, so roughly half of the length is blocked. According to this values, do you think ı should opt for a smaller pump?
http://www.reefcentral.com/index.php...flow-size-calc
Regards
nanoreef13
New member
This is an awesome page! So much info its like reading a book!
uncleof6
Active member
Minimum flow for a 1.5" pipe at siphon is well over 3000 gph. I do not know what the flow calculator is using to determine the size vs flow rate, however it is inaccurate by a huge amount for either open channel (durso) and for siphons.
@ 1300 gph you could use 1" siphon, and dry emergency, and a 1.25" open channel and not have any worries. As long as you follow the basic design guidelines. No way do you need to get a smaller pump. Cut the teeth off the overflow and let it flooooooooowwwwww.
Also, use 1" pipe for the return line.
Firochromis
New member
Hi Uncle,
My initial plan was to apply beananimals' system but I found this aquarium cheap and in good shape. My problem is there is only one drain and that is 1.5" Should I use it as siphon or durso?
I have a plan for the emergency line, but this is not dry I'll install a water level sensor in the aquarium above the water level. If, for some reason my drain is blocked, the water level in aquarium will rise. And when the installed level sensor activated, it will cut the power of the return pump. This will have two benefits:
1. Return pump will be saved running dry,
2. When the power is cut the return line will suck the water from aquarium to sump and work as an emergency line.
My initial plan was to apply beananimals' system but I found this aquarium cheap and in good shape. My problem is there is only one drain and that is 1.5" Should I use it as siphon or durso?
I have a plan for the emergency line, but this is not dry
I'll install a water level sensor in the aquarium above the water level. If, for some reason my drain is blocked, the water level in aquarium will rise. And when the installed level sensor activated, it will cut the power of the return pump. This will have two benefits:1. Return pump will be saved running dry,
2. When the power is cut the return line will suck the water from aquarium to sump and work as an emergency line.
uncleof6
Active member
Hi Uncle,
My initial plan was to apply beananimals' system but I found this aquarium cheap and in good shape. My problem is there is only one drain and that is 1.5" Should I use it as siphon or durso?
I have a plan for the emergency line, but this is not dry
1. Return pump will be saved running dry,
2. When the power is cut the return line will suck the water from aquarium to sump and work as an emergency line.
Until the precise time you really need it, then the level senors will say " not today," and you will have water all over the floor. Do not rely on devices mechanical, electrical, or a combination of both, to prevent a flood. Design will not fail you, everything else will.
A single siphon line, 1.5", will not be safe to run--without an equal size dry emergency. A single Durso style stand pipe, 1.5", will not handle anywhere close to the flow that red dragon will put out, and you don't want to cut it back to 350 gph, so your drain will work. Simply a waste of a pump. You want to use a great pump, then pick up a tank, that is not capable of it, unless you take a glass hole bit to it. Sorry, just the truth.
Last edited:
Firochromis
New member
uncle, at the moment changing the aquarium is not an option for me. I hardly persuade The Boss, another conversation about a different aquarium would probably end with a 50 g system.
You said
How rigid is that statement about being the same size? I can't add more drains to the current aquarium but, I can use the current 3/4" return line as a dry emergency. Then I an add a return line (or two) coming to the aquarium not from the drilled holes but from above. This will definitely hurt the aesthetics but I can do it.
Would this design be safe enough? If this also so-so, I mean if this is not "yeaahhh this is it!" solution then maybe it is better to use durso and a smaller pump (Red Dragon 4500) and save the plans for the next aquarium.
You said
How rigid is that statement about being the same size? I can't add more drains to the current aquarium but, I can use the current 3/4" return line as a dry emergency. Then I an add a return line (or two) coming to the aquarium not from the drilled holes but from above. This will definitely hurt the aesthetics but I can do it.
Would this design be safe enough? If this also so-so, I mean if this is not "yeaahhh this is it!" solution then maybe it is better to use durso and a smaller pump (Red Dragon 4500) and save the plans for the next aquarium.
uncleof6
Active member
It is inflexible.
The answer is the smaller hole being the main siphon, and the larger hole being the dry emergency. Very simple. 1" siphon, on the 3/4' bulkhead, 1" or larger, dry emergency on the larger bulkhead. This is referred to as a "herbie," and is not Bean's design, and does not function in the same manner.
rrasco
New member
The drains are on the left of my C2C. I don't know what effects it may have, but it works. I do occasionally see waves from one side to the other, but they are not noisy or seem to affect anything.
Similar threads
