Silent and Failsafe Overflow System

[jetfixr]

Ok I looked at several pages of this thread and have come away more confused then anything else. Maybe you guys can answer some questions for me. I am setting up a new tank and I would like to get this right. It is a 90 with a 30 sump and a eheim 1260 for a return. I guess it will be pumping 400 gph after head loss, if I decide to go with a larger pump it would be a eheim 1262 which would probably be no more then 600 gph after head loss. It seems to me that most guys in this thread are running massive amount of water. I have MP40s for water movement in the tank and I have ran a 1260 on a similiar tank before with dursos, it all worked well with that amount of flow. My main question is with the plumbing size. I see people running 1 1/2 pvc and it just seems like overkill. I mean at some point (even with a gate valve to adjust flow) wouldn't that size of pipe make it hard to maintain a siphon. At full siphon a 3/4" pipe can move almost 1200gph, 1.5" pipe will flow well over 4000 gph. Just sounds like overkill as far as the siphon pipe is concerned. Now I know that smaller pipe is a clog hazard, but if you have the gate valve cranked down on a larger pipe, wouldn't you have that same clog hazard at the point of the gate valve? Ok, that covers my concerns on the siphon pipe.
Now on the open channel I guess noise has been stated as the main reason to run a larger pipe. From how I understand things, this pipe should carry an extremely small amount of water. I would think that a 3/4 or 1" pipe should be able to flow 50-100 gph silently. As far as safegaurds go, the open channel should go into full siphon mode if the primary tube clogs, that is the reason for the 1/4" air line. If the open channel clogs, the same will apply for the emergency pipe.
I am just trying to understand the need for the larger plumbing. With a smaller tank, you have a smaller sump area. Space is an issue! If you start running all kinds of 1 1/2 plumbing, true union valves alone are huge, you are gonna be all bulked up on plumbing and will have very little area left in your sump area. Cost of larger plumbing is another issue. In my opinion, I would not let cost be a deciding factor but I also don't like to spend cash. needlessly.
Sure you could drop a big block Chevy motor in a VW bug, but what would be the point? I like the idea of a silent overflow but would like to scale it back a bit to fit my application.

 

[BeanAnimal]

I see people running 1 1/2 pvc and it just seems like overkill. I mean at some point (even with a gate valve to adjust flow) wouldn't that size of pipe make it hard to maintain a siphon. At full siphon a 3/4" pipe can move almost 1200gph, 1.5" pipe will flow well over 4000 gph. Just sounds like overkill as far as the siphon pipe is concerned.

Yes... for 400 GPH it is likely overkill. However, do consider that a 3/4 orifice may clog at a single point, but a 3/4" pipe can easily foul anywhere along its length. Organic matter does quickly accumulate in our standpipes. I have seen 1.5" pipe almost fully blocked by fanworms, sponges and calcification.

Now on the open channel I guess noise has been stated as the main reason to run a larger pipe. From how I understand things, this pipe should carry an extremely small amount of water. I would think that a 3/4 or 1" pipe should be able to flow 50-100 gph silently.

The area of the pipe is what is important. Moving below 1" severely limits the ability of the pipe to flow in open channel mode.

For 400 GPH, you may be able to get near silence with (2) dursos. Equip them with fail-safe airlines and get added safety. As has been mentioned before, there are many ways to create a quiet and safe system. My design is simply a one-size-fits all method that is predictable and easily repeatable

 

[jetfixr]

Thanks for the reply bean. I would really like to implement your overflow design in my next tank. I was trying to scale things down a bit because I wont have the luxury of a bunch of space in my sump area, and I don't need to handle a whole lot of flow. I think what I will do is use 1.5 inch bulkheads, use 1" bushings and run 1" plumbing from the bulkheads. That way I can see if I can duplicate your success on a smaller scale with the decrease flow of my tank. If I have to run 1.5" pvc, the bulkheads will already be installed for it. All I will have to do is pull the bushings. Not quite sure how you could increase the size if it was only drilled for 1" bulkheads.

 

[BeanAnimal]

My system is setup with 1" bulkheads that feed the larger tees and standpipes. The larger diameter section of the open channel that is below the TEE is the critical section, as that is where the air and water are in a common pipe.

 

[MavG]

Ok, so after the first part of the thread and then to my dissapointment i got to the end and saw that it had been split after thinking i had got up to date, and then saw that the second half has 185 pages, i got a little depressed and quite honestly, i dont have the patience to read everything lol.

So bean Animal, mate, love the plumbing idea, and have been seeing it for some time, currently designing a large tank with around 14,000LPH (about 3700GPH) flow through the sump.

Do you think 3 x 1.5" bulkheads running 1.5-2" pipes would be good enough for this amount of flow, or would it be safer to upsize to 2" bulkheads?

Alternatively, if 2" isnt enough, could i just run a second open channel or siphon pipe? and have 2 siphon drains to get the flow?

 

[noplay180]

C2C finally attached all 95 inches. Now I have a problem the elbow won't allow me enough space to thread into bulkhead.

Sent from my MB855 using Tapatalk 2

 

[MavG]

Any ideas Bean? re my last post

 

[BeanAnimal]

You should be fine with 1.5" plumbing and bulkheads. 2" certainly would not hurt.

Sent from my Commodore VIC20 using NovaTerm

 

[noplay180]

Bean I have approximately 4500 gph flowing thru my sump, and I have already drilled for 1.5 bulkheads do you think i should go upp in plumbing size from the plumbing on the outside

 

[sean04]

Sent from my Commodore VIC20 using NovaTerm

Really? Isn't this an ancient system...lol

 

[Floyd R Turbo]

Classic. Best "sent from" footer I've seen

 

[_Mackus_]

Bean,

I set up my system using your exact design and everything has been working great. It's been up and running since November with no issue until recently.

Now, when I shut off my pumps to feed my fish and then turn them back on, the water level in my overflow box goes higher than it was before shutdown, which (sometimes) can cause the water level in the return pump chamber of my sump to drop to where the pump is pulling in some air. A quick easy fix for this is to turn the ball valve to fully open on the siphon pump, lowering the water level in the overflow, raising the level in the pump chamber, and then I set the valve back to where it was before and things go as normal.

Any idea why the setup may be doing this, though? It was fine since installing until the last couple weeks. I've made one slight change to my system in that time, which was to add a drain pipe to the output of my protein skimmer to stop it from splashing. Could that somehow be affecting the overflow system? The drains from the siphon and open-loop both go into the part of my sump where the skimmer is located. Only other thing I could think of is perhaps a blockage in my drain tubes, such as algae or something, but I've got no way of checking for that.

Thanks again

 

[chrishet]

This has to be one of the Top Ten threads on RC!

Question: How critical are the 90's in the overflow box? Can I get away with something like this?

<iframe width="560" height="315" src="http://www.youtube.com/embed/XaYI7Dp_Fgg" frameborder="0" allowfullscreen></iframe>

 

[gweston]

Really? Isn't this an ancient system...lol

@Bean

I wasn't lucky enough to have a powerful Vic20. Instead I used a TRS80 that it could only display/type in ALL CAPS.

@Noplay180

What is your dimensions for your overflow? I ran into a somewhat similar problem with a 40B overflow I just finished up with. My bulkheads and elbows fit just fine. My problem that that I was 1/4" short to properly fit in my lockline return plumbing.

Lets just say, I fixed the problem with lubricant, muscle and luck. I got the locline in without busting the overflow. Barely. RTV100 was strong enough to handle a bit force.

What I found was a good size for an overflow is about 4" high x 3.25". But for locline, go at least 4"x3.5". That is just enough to squeeze in a 3/4" locline fitting + a 3/4" locline elbow to go up and around the overflow.

Next tank. The return isn't going to be in the overflow. The 125g I am finishing up with this week has returns not in the overflow. Easier to deal with.

What can you do now? I have heard some people cutting the bulkhead threaded end short, so the bulkhead could slip into the tight space. The only problem with that is the cut down end of the bulkhead might be problematic to plumb.

 

[drock59]

How is everyone supporting the PVC coming out of the overflow? Without any support all the weight of the plumbing hinges on the bulkhead.

 

[jdcook72]

Question: How critical are the 90's in the overflow box? Can I get away with something like this?

I was thinking of doing something very (almost exactly, actually, assuming the bulkheads in the corners are returns) similar to this but I didn't think it work without the 90s because the full siphon couldn't be maintained as water would entering the open channel pipe at the same time and rob flow from the siphon. I think it works with siphon and open channel at the same level when using the 90s because the 90 effectively makes the entry to the drain horizontal so water cannot flow to the open channel until capacity of the full siphon is exceeded.

One option I considered would be to drill the bulkheads so the bottom of the open channel was just above the top of the siphon and the bottom of the emergency just above the top of the open channel. I think it would work that way but would require the overflow to be taller to accommodate the spacing. I didn't like that idea, mostly for aesthetic reasons.

After seeing your design though, I think it could be accomplished with a few tweaks and an additional baffle in the overflow box. The key to remember is that the open standpipe should not receive any flow until the siphon is at capacity and the emergency standpipe shouldn't receive any flow until both the others are at capacity. You would need to add a baffle between the siphon and open standpipe that came up to just above the top of the siphon. The baffle between the open and emergency standpipes only needs to be the same height because the chamber created for open standpipe should only ever have a little water in it as it is just collecting and immediately draining the overflow from the siphon.

Now, the other key issue with this is that water overflowing into the box can only enter the siphon chamber directly. Access to the other pipes must only be made by water breaching a baffle, otherwise you would have the same issue as with the original design without the 90s. One solution for this might be to create a "shelf" inside the box, over the open and emergency bulkheads that directs water to the siphon. This way you can take advantage of the full distance across the top of the box for skimming area. I'll try to do a quick sketchup to illustrate the design.

I'm anxious to hear some feedback on this idea as now I think I can consider going with a low profile box sans 90s again. Collaboration is a good thing.

 

[jdcook72]

I'll try to do a quick sketchup to illustrate the design.

Here you go. No dimensions, scale however you like, just the basic configuration I was thinking. From left to right, full siphon, open air, emergency.

 

[chrishet]

Very interesting - I LIKE IT! Here are a few updated sketches from my original sketch....someone on another thread mentioned an issue replacing bulkheads in a narrow overflow like this...good thought...so I cut away a bit of the back on these...I also raised the open channel a bit.

 

[chrishet]

Here you go. No dimensions, scale however you like, just the basic configuration I was thinking. From left to right, full siphon, open air, emergency.

One issue I see with this design is cleaning the overflow...that ramp would have to be removable don't ya think?

 

[chrishet]

One other thing I have been concerned about is creating a vortex above the full siphon drains and letting in air. Could something like this work to help prevent? a cutaway piece of a PVC adapter would work...