PVC Overflow

[Pokerman11]

After doing a bit of research I'm down to using this design for a DIY overflow for my referigum to sump.


Here is the video I found: Uaru Joey


https://www.youtube.com/watch?v=65y...feature=iv&annotation_id=annotation_561674341

My flow is only about 120gph so thinking that 1" pipe will be fine. This setup is in a basement pump room, so I'm not worried about the noise.



If anyone can suggest a different design I'm interested This look good and easy to build.

 

[uncleof6]

Well, they actually do not work as advertised, the flow rate in the video is <20 gph. In 1" you will likely get ~50 gph without running into trouble. It is the dynamics of open channel flow, that will win. Once the pipe is 1/4 full of water, you are done.

 

[zachts]

Actually I have one that runs 1" thin wall pvc and can handle the full output of a mag 5 though just barely. I'd not run it past 250 gph, and I also have a aqua lifter maintaining siphon just for good measure.....

the RC overflow calculator has it running around 500gph but that is definitely pushing it as I can attest to having built and tested one for basement frag tank use.

if in doubt run two one 1/2" at full siphon dialed back with a valve and a 1" barely going as emergency.

 

[scott3569]

I did the same one..here is a video on mine.
https://www.youtube.com/watch?v=WfryCrshmpo

 

[uncleof6]

Folks like to raise a fuss, when I comment that they do not work as advertised. The simple truth is they do not, and they are not conducive to surface skimming/surface renewal. Just the way it is. You are far better off purchasing an HOB overflow, which at least, despite the open channel physics of the drains in the external box, provides some modicum of surface skimming/surface renewal.

Maybe a second diagnosis is in order:

http://reefcentral.com/forums/showpost.php?p=21091770&postcount=2

 

[scott3569]

I would gladly see the proof that they don't work as much as people say they do, as above you can see my video, please take a look at it educate me..I am extremely new, don't have any plumping experience per say..but from what I am experiencing it does work..But I am also open, to see how it doesn't..I am not saying it is the best thing out there, it not by a long shot..But I have yet to see videos of them not working.

 

[Pokerman11]

Actually I was putting together my parts list to do 2 of these PVC things.

In the end I just hit Amazon buy it now on a HOB overflow. For about 60 bucks in the premade HOB seemeds to be the way to go.

 

[scott3569]

yeah that is a way to go, just be careful some of those HOB overflows are even worse, before you buy it, look at the reviews and ask here. make sure it is not going to be a problem

 

[Mpy]

If you have a PVC overflow like the one in the video you will not be able to move much water through it without having it become noisey. If you build it so that the PVC overflow is pulling from an overflow box or something then it will work much better and can be run at a higher flow rate.

I have a 1" thinwall PVC overflow that pulls the water out of a 4" PVC overflow box(pipe) and it handles about 300gph perfectly fine and could probably handle 400gph. Siphons by their nature are variable flow, so your flow will be determined by the height of the water above the siphon break on the overflow.

Now, if you want a slow flow rate from your refugium into your sump, and you don't mind if it gets noisy, go ahead with the design from the video you posted, but make sure that you have the clearance above it so that it can pull a full siphon if it needs to.