Silent and Failsafe Overflow System
- Thread starter JohnL
- Start date
My water line is about 3/4" down from the rim, should I lower my weir another 1/2 to bring that water line down?
Also It appears that the layer of water going over the toothless weir is about 3/16 of an inch. Would you consider that good or should I go for a longer weir which is currently only 18" long on a 36" rimless tank.
Again thank you for your help
uncleof6
Active member
Surface agitation is necessary for gas exchange, however, a return outlet just below water level, ususally provides sufficient surface agitation for gas exchange purposes. Over use of powerheads, mixes dissolved organics back down into the tank, rather than having them "skimmed off" by the weir. This reduces the concentration of organics reaching the skimmer and reduces the skimmer's efficiency, and increases the dissolved organic levels in the tank, which causes declining conditions...
Water level in the overflow, should be ~1" below the top of the weir. The weir should be set 1" below the top of the glass (1.5" below the physical top of the tank.) You have to think on this a bit, to really get it, however, the water line in the overflow using a siphon system will be around the top of the down-turned elbows. The holes are centered low enough on the back to keep the water level at the top of the elbows, while maintianing the 1" drop into the weir. I calculated it out, and the hole centers (given above parameters) need to be a minimum of 2 3/4" down from the top edge of the glass, (3 1/4" down from the physical top of the tank) for 1" bulkheads. Larger bulkhead holes need to be adjusted accordingly to maintain the 1.5x hole diameter from edges of glass and each other. Takes some good measuring, with plumbing in hand, to get it set.
With the weir at the top of the holes, either the weir is too low, or the holes are too high. I have seen your thread, however, have not taken a close look at the images.
uncleof6
Active member
Water level should be where you are comfortable with it. I use 1", but I have experienced trust for this drain system. Some are not comfortable with the waterline that close, so 1.5" is not unreasonable.
3/16" is not horrible. Lengthening the weir to full length of the tank, will improve the efficiency of the system, and allow you to bump the flow rate up to further improve the system efficiency (multipass system not a single pass system,) without losing surface skimming efficiency. The ends of the overflow count too for length...with the total weir length, inside width of the tank (river,) and accurate measure of the head height behind the weir (thickness of the water layer going over the weir) you can calculate the flow rate of the system...that is what weirs are for.
The idea behind the 'water thickness' over the weir, is water closer to the weir, moves faster than water further from the weir. So the thinner the layer, the more surface water goes over rather than subsurface water.
Ok, back to bean's drain system.
Syntax1325
Acro Addict
One question: My design requires a 45 degree elbow so my last several inches of pvc can enter my sump vertical. Does this piece of pvc need to be glued for the drains to work properly?
My first thought is that they do to prevent an air leak... Just checking though.
My first thought is that they do to prevent an air leak... Just checking though.
Will this work? BA overflows, horizontal runs, gravity feeds, oh my!
I plan to have a DT in my living room, and a sump and a separate refugium in an adjoining room. I would plumb the DT into PVC in the wall, and from there I'm thinking it's at least 8 to 10 feet of horizontal PVC just running through the wall until it reaches the other room... and then of course eventually back to the DT.
I plan to have a BeanAnimal overflow on the DT , so I will have those 3 pipes running through the wall and then they will eventually empty into a sump in my "fish room." There will be a net decrease in height between the DT and the sump of course, but I guess my first question (in addition to "will this work") is - should I have the drop occur right away (so DT overflow to vertical drop to horizontal run to sump) or after the horizontal run? (so DT overflow to horizontal run to vertical drop into sump)
That sump will then pump up to a refugium (situated fairly high up in the fish room), which will also have a BeanAnimal overflow. The main siphon line from that overflow will feed back to the DT (so that's a fourth pipe running back through the wall), and the other two lines will just empty back down to the sump.
Will this work? Another poster reasonably suggested that the siphons may have trouble establishing with so much horizontal run - anyone have any experience with this kind of thing?
I plan to have a DT in my living room, and a sump and a separate refugium in an adjoining room. I would plumb the DT into PVC in the wall, and from there I'm thinking it's at least 8 to 10 feet of horizontal PVC just running through the wall until it reaches the other room... and then of course eventually back to the DT.
I plan to have a BeanAnimal overflow on the DT , so I will have those 3 pipes running through the wall and then they will eventually empty into a sump in my "fish room." There will be a net decrease in height between the DT and the sump of course, but I guess my first question (in addition to "will this work") is - should I have the drop occur right away (so DT overflow to vertical drop to horizontal run to sump) or after the horizontal run? (so DT overflow to horizontal run to vertical drop into sump)
That sump will then pump up to a refugium (situated fairly high up in the fish room), which will also have a BeanAnimal overflow. The main siphon line from that overflow will feed back to the DT (so that's a fourth pipe running back through the wall), and the other two lines will just empty back down to the sump.
Will this work? Another poster reasonably suggested that the siphons may have trouble establishing with so much horizontal run - anyone have any experience with this kind of thing?
I confused myself. What I meant was the top of my weir(full length) would be 1" from top of the my tank(rimless) and the holes I'm drilling will be 3.5" from top of tank to center hole. From there I need to measure out just how high the internal overflow should be to give me 3/4" between the bottom of the overflow to the bottom of the 2 turned down elbows. Please tell me I'm right? Lol I feel like I'm overthinking.
We are on the same point, how deep overflow should be? Hopefully Uncle can see the question before its too late. Drill job due tomorrow.
Mrramsey
NEO Reefer
its easy to over think this. for me my overflow box was 5" deep. the distance from the top of the glass is the last thing to figure out. measure backward to calculate the depth of the overflow. 3/4" between the bottom of the overflow and the down turned elbows + the height of the elbow fitting + 1.5" to 2" to the top of weir. that will give the depth of the overflow itself.
Perfect Mike, thanks. I will put bulkheads then measure the final distance before mounting the overflow.
uncleof6
Active member
I can't believe you can't find those street elbows at a local store. You have a Home Depot around?
http://www.homedepot.com/p/Mueller-Streamline-1-1-4-in-PVC-Schedule-40-Pressure-90-Degree-Spigot-x-Slip-Street-Elbow-409-012HC/100207905
Yea I have a Home Depot but isn't that a 1.25" x 1.25"?
Mrramsey
NEO Reefer
I found my 1.25 x1 at Lowes however it was not a street. I just trimmed the 1" side down leaving 1/4" of flange to glue in a small piece of 1" pipe.
uncleof6
Active member
Home depot has a lot of stuff hidden away, among other stuff in unlikely places (that should not surprise anyone ) But home depot, as well as other big box stores, suffers from a lack of some of the more useful, but less popular fittings, the reducing street el being one of them. Though they may have 1 hiding somewhere, irrigation suppliers are a better place to look for this type of fitting and many others...
) But home depot, as well as other big box stores, suffers from a lack of some of the more useful, but less popular fittings, the reducing street el being one of them. Though they may have 1 hiding somewhere, irrigation suppliers are a better place to look for this type of fitting and many others...Oops. That it is. My bad.
I'd also be interested in hearing some opinions on this.
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