Silent and Failsafe Overflow System

[jdcook72]

... an issue replacing bulkheads in a narrow overflow like this...I also raised the open channel a bit.

Minimum clearance inside the overflow, front to back should be where there is enough room for the bulkhead to fit before it is pushed through the hole. If you cut the threaded portion of the bulkhead to the minimum leangth that still leaves enough purchase for the nut on the backside, that would be the clearance you need.

Unless you raise the open channel to where its lowest point is above the highest point of the siphon, I don't see any functional gain.

I will be making my overflow from acrylic and will be a full box as in the picture. The box will be held to the DT by the bulkheads. making the shelf removeable for cleaning is a good idea. Regarding vortices, I think I remember reading somewhere in the thread that they are not an issue do to a combination of the small volume in the box (made even smaller without the 90s), the turbulent flow in the box and the proximity of the opening to the wall of the box. The last factor does not come into play when the 90s aren't used but maybe adding another baffle that could be slid into place after installing the bulkhead could be done if necessary?

After a certain point, it becomes an exercise of overthinking the solution to a problem that already has an answer... but I supose that's how we got the current answer in the first place.

 

[jdcook72]

I don't know how water tight the joint would be or need to be but this might be another option that enorporates making the shelf removable and installing/replacing the bulkheads easy. Maybe some type of a reef safe silicone gel lubricant schmutz, if there is such a thing, in the dado would make it water tight enough.

 

[jdcook72]

Here's another view that might give a better idea of how it works. Basically have the front off the box and attach it to the DT using the bulkheads, gasket between the flange inside the box and gasket between the box and DT, nut on the back of the DT. Plenty of working space. Once the overflow is in place, slide on the front. Done. I don't know if you could use something like Vasoline in the groove and on the edges of the baffles to keep everything water tight? I wouldn't think there's a lot of preasure at the top of the tank and it doesn't have to be truely water tight as long as a little water is only seeping into the box since it's just going down the drain anyway. You could slide off the front of the box and clean everything out whenever you wanted, during a water change and you wouldn't even have any water to deal with. Does anyone know if that type of joint would work or if Vasoline or something like it would work?

 

[Nailbender]

cool i might use this on my 250

 

[chrishet]

JD, what kind of flow rate are you thinking?

I have done dado joints before using acrylic...you have to be careful when cutting them and they can be quite fragile if cut too deep.

 

[jdcook72]

JD, what kind of flow rate are you thinking?

I have done dado joints before using acrylic...you have to be careful when cutting them and they can be quite fragile if cut too deep.

I have know idea on flow rate. I was planning to use this on a 30 gallon cube (old style Oceanic w/seams, not a Biocube) at about 10x turnover. I'm going to set it up with a sump/fuge so I can have a dragonet in there with lots of pods. I was thinking that since the overflow calculator doesn't mention box volume specifically, only pipe diameter and linear overflow size, that as long as the linear was right it should be able to feed any drain as long as the length is right.

Since I don't think the dado needs to be structural, there will be more weight pushing the front place up against the baffles, 1/8" in a 1/4" thick piece would be sufficient. The only tricky part might be getting the blind dado right in the bottom piece (or sides depending on wich way you go) to keep it sealed up.

 

[chrishet]

I have know idea on flow rate. I was planning to use this on a 30 gallon cube (old style Oceanic w/seams, not a Biocube) at about 10x turnover. I'm going to set it up with a sump/fuge so I can have a dragonet in there with lots of pods. I was thinking that since the overflow calculator doesn't mention box volume specifically, only pipe diameter and linear overflow size, that as long as the linear was right it should be able to feed any drain as long as the length is right.

Since I don't think the dado needs to be structural, there will be more weight pushing the front place up against the baffles, 1/8" in a 1/4" thick piece would be sufficient. The only tricky part might be getting the blind dado right in the bottom piece (or sides depending on wich way you go) to keep it sealed up.

JD, what I meant by fragile is the female joint can crack or split if it is not thick enough, and given that you want this to be free (i.e. not glued) it may present an issue when sliding the front wall in and out....

Good luck with your tank build, I am sure it will awesome. I had a 30 gal cube years ago...my thread got split like 4 times!

http://www.reefcentral.com/forums/showthread.php?t=641219

Btw, I put a mandarin in this cube after it was up for a few years (my tank was overflowing with pods) but after a week the mandarin ate em all up...and ended up starving....they are challenging but there is a lot of good info out there on how to keep them alive...good luck

 

[jdcook72]

JD, what I meant by fragile is the female joint can crack or split if it is not thick enough, and given that you want this to be free (i.e. not glued) it may present an issue when sliding the front wall in and out....

I got what you meant by fragile, what I was saying is that the dado wouldn't need to be super strong to hold the front in place so maybe an even shallower one would be fine, just enough to set its position, like 1/16". That in 1/4" thick material should still leave it structurally sound. If it looks lie flexing is an issue, which I don't think it would be at this small size, I could put braces in from the top corners to the outter baffles to make sure the front stays locked in place.

I will check out the thread too, I'm sure there will be some good information in there for me. I've started a thread as well for my tank, only questions regarding my sump at this time.

http://reefcentral.com/forums/showthread.php?t=2160399

I put a mandarin in this cube after it was up for a few years (my tank was overflowing with pods) but after a week the mandarin ate em all up...and ended up starving

That's what I've read is a big issue with the dragonets, they will devour a thriving population. For this reason, the sump refugium I'm trying to design is almost as big as the DT. Hopefully this will be enough isolated space to keep the pod population healthy.

 

[drock59]

Folks, I am in need of some help.

I am setting up a new 75g tank with this overflow. Today I decided to test the system. Unfortunately,it isn't working.

I have to have all three channels fully open or my tank will overflow. With all three open, the water level in the overflow rises until it needs to siphon, then it flushes.

The return pump is Mag drive 9.5 with at least 3' of head. According to the manufacturers charts, I am pushing somewhere in the 700-800gph range. I used all 1" pipe and bulkheads.

Ideas?

 

[drock59]

 

[jdcook72]

...Unfortunately,it isn't working. Ideas?

From the picture I don't see any 90° elbows? I think you might be suffering from what I suspected would be an issue above with Chrishet's design. A full siphon can't be maintained because the open Chanel is robbing flow from it before it reaches capacity. I don't see an air vent on any channel either?

 

[noplay180]

Folks, I am in need of some help.

I am setting up a new 75g tank with this overflow. Today I decided to test the system. Unfortunately,it isn't working.

I have to have all three channels fully open or my tank will overflow. With all three open, the water level in the overflow rises until it needs to siphon, then it flushes.

The return pump is Mag drive 9.5 with at least 3' of head. According to the manufacturers charts, I am pushing somewhere in the 700-800gph range. I used all 1" pipe and bulkheads.

Ideas?

Where are the down turned elbows

Sent from my MB855 using Tapatalk 2

 

[drock59]

I put the elbows on and I have the same problem.

It's like the siphon is not starting. The open channel pics up the slack when the water level gets too high, but the siphon is not starting on its own.

http://www.youtube.com/watch?v=O51D_XpXgLs

 

[Chappy]

Try raising the airline tubing. I don't think it should be that low. It is meant to start a siphon when the water level is raised above what the up turned elbow can handle. You might not be purging all the air out of the full siphon.

 

[jdcook72]

how deep in to the sump are the discharges from the drains? I think I read somewhere in the thread that they shouldn't be too deep or that will effect the siphon starting as the air won't purge.

 

[chrishet]

how deep in to the sump are the discharges from the drains? I think I read somewhere in the thread that they shouldn't be too deep or that will effect the siphon starting as the air won't purge.

I would be interested to understand this better as well....BTW, I did update my design with suggestions....here is my latest...I'll need to play around with the baffle wall heights....

 

[drock59]

Discharging 1" under water in the sump.

The system works if I turn the siphon 90 T up to let air out, but it will not start on its own. The open channel simply handles the flow and the siphon never starts.

Any help appreciated.

 

[drock59]

Seems to work fine with the siphon T turned sideways, however in this configuration the open channel is sucking down lots of water and air, which defeats the purpose.

Another thought: possible the siphon bulkhead is too high in the overflow?

Forgive my ignorance. I thought this would be straight forward, but it's not turning out to be.

 

[jdcook72]

View attachment 186790
Seems to work fine with the siphon T turned sideways, however in this configuration the open channel is sucking down lots of water and air, which defeats the purpose.

Another thought: possible the siphon bulkhead is too high in the overflow?

Forgive my ignorance. I thought this would be straight forward, but it's not turning out to be.

If a full siphon is forming and tuned correctly, the open channel shouldn't have much volume to flush. I think the siphon is supposed to be set to where it is taking almost all of the overflow water, that way it never flushes completely. The little bit that would accumulate is what the open channel handles, a relatively small amount. Is the full siphon closed down too much?

The bulkead positions could be off a little and that could affect things I suppose. Try it with the siphon at 6 o'clock, the emergency at 12 o'clock and put the open chanel about 2 o'clock. That way the siphon will get a little more time to establish during initialization before the open chanel starts pulling any water.

Just some things to try, I haven't done one of these yet myself but I've been reading a lot as I'm getting ready to do my first.

 

[active]

i was messing with mine this weekend and was adjusting the flows and fount that with the valve open all the way on the main or primary drain the system didnt function properly. i closed it just about 1/4 or less and it worked awesome. i have some flow thru the secondary pipe as well and am happy about that because i turned that pipe into an algae scrubber. the emergency is used when the system starts up after a power outage or to shut off to feed. i didnt time it exactly but i think that within 30 seconds of the return pump turning on the siphon starts. the emergency works for like 5 seconds during this time and the secondary just flows maybe 20% overall.
i dont know if this helps you or not but its what i found when playing around to see what all happens when things are messed with.