Silent and Failsafe Overflow System

[coralcruze]

I have a question. Not sure if anyone asked this or not but... I'm planning a closed loop system for water movement so my question is will your system work with any turnover rate? If I have a very small pump feeding water to the main tank, wouldn't a full siphon be too fast to drain this very slow flow? I think I know the answer to my own question but want to be absolutly sure its correct

 

[TheFishMan65]

That is what the valve is for. To tune make the pipe seem smaller so it is just big enough (or small enough) to create the siphon and not go to fast or too slow.

 

[mrx66699]

What size pump and how are the standpipes configured? Looks like dursos or some kind of air assisted siphon? Are you willing to drill a third hole?

bean he is using a regular dart pump and there are no stand pipes he needed to tell you the overflow is a glass holes overflow. The two pipes coming out the back are just straight drains (air/water mix)

He has the glass holes 1500 overflow and the return pump is rated for flow 3600 USgph @ 0'. I am correct in saying its easy to see that a 1500 gph straight drain no siphon overflow is not going to keep up with this pump even at the obvious more than 0' head.

He can still utilize your style of overflow. He will gain some gph and get rid of most of the micro bubbles in his sump without cutting another hole by converting the flow (air/water) of his current style plumbing into a full siphon.

All he has to do is put the beananimal configuration on the outside of his tank in a staging area on the back of the tank and have the two 1.5" drains flow directly into it. Thus converting it from air plus water in the drain pipes of his current configuration into one full siphon in yours.

Just build a box out of acrylic on the back housing your configuration being fed by the two 1.5 bulk heads. Now you would get the best of both worlds surface skimming and the silent and failsafe overflow system.

 

[T-Hunter]

Tricky Display / Sump Configuration

Tricky Display / Sump Configuration

Bean -

I apologize in advance if you have addressed this previously. I did try to read this thread from the start to find my answer ... I am about half way through (and two hours later) ... so I have decided to shortcut and see if I could get a more direct answer.

I have a tricky situation. My sump is in another room from my display - as in 6 feet laterally. So once my standpipes drop about 24 inches - they then travel horizontally 60 inches to the sump. (Note: I have thru-holes in the bottom of my tank).

Knowing that this is a tricky situation I have built a "cheaper" (relatively) mock-up version of the system in my garage with all of the appropriate hydraulic parameters. Nothing like throwing away $100 worth of materials - but after the fact I'm glad I trusted my gut and did not start in-wall install until everything was just right - because I discovered a real problem.

System works beautifully during operation. I have (3) 1" standpipes - and have taken everything up into the 2000gph regime (estimated) during testing. The problem (as I am sure you have already spotted) is that due to the length of the horizontal travel at the bottom of my standpipes - the system is not self-siphoning on start-up. There is an effective air lock created as the initial air in the full-siphon pipe is trapped. So I have to bleed this manually and then things work - but this is obviously not going to be the solution. I need a set and forget solution.

I have been brainstorming solutions and have come up with two:

1. Eliminate the durso style top to my siphon and go with only a vertical standpipe. Also, place this about 3" below water level (I have 20" to play with in my in tank overflow area) and live with the added drain into sump during power off. I would imagine that on startup the water will get purged out the top in the overflow area - since the air in the pipe can escape straight up. If I have vortex problems I could go to a disk type suppressor or the like. I am going to the garage shortly to test this.

2. Go to an electronically driven system to either keep the full-siphon primed upon shut off - or electronically purge the siphon with some kind of float arrangement on startup. I hate this approach though since I have thrown the elegance of the design out the window, introduced system complexity, added more places for failures, not to mention costs of solenoids, floats, valves, etc, etc.

I have racked my brain trying to think of other passive alternatives. I thought I would run this by you in the event there is a clever solution.

BTW - The contribution that you have made to the community is amazing. Clearly you have a great passion for the hobby - but also in engineering - and doing things right! It is greatly appreciated! Thanks.

 

[afgun]

I have racked my brain trying to think of other passive alternatives. I thought I would run this by you in the event there is a clever solution.

While not cheap, you might also investigate an automatic mechanical air-purge valve such as those at http://www.plastomatic.com/venting-valves.html

 

[T-Hunter]

afgun -

Good call. Was unaware that they even existed. It appears that one of these on my full-siphon down pipe would do the trick.

I have to admit though that at $150-$200 for a piece of plastic ... it has me a little reluctant ... and a bit sick to my stomach. Yikes.

With a price like that I'm motivated to build my own ... it makes me wonder if a spring check valve - with the spring removed, a buoyant substance attached to give the float, and possibly a little better seal might do the trick. That would be closer to $15. Hmmm...

If I get the guts to buy one and play with it ... I will post.

In the mean time. I did test the system without the top Durso-like bend to the full-siphon pipe. I put it about 2" below the water line with about 600-700 GPH of flow. It worked ... I did notice though that I couldn't tune the full-siphon right at the limit as in 99% of full siphon and 1% open channel. In this "right on the edge" setting - I could not get through the turbulent vortex flows on the full siphon pipe. Must be during the vortex - flow rate increases slightly - thus pulling down my head level - then only to kill the vortex an flow rate - and then the process repeated. I was getting an oscillation. It may have been damped ... meaning if I waited long enough it may have gotten through .... but after about 5 minutes ... I just decreased full-siphon flow a little and this appeared to get it past the oscillating vortex stage. The only problem is this added open channel flow gives a very small trickle sound now. I really want to achieve the true silence !!!

But I am using 90 degree and 1" in the open channel. I think there is too much turbulence over the 90 deg edge and especially with the lower limit of diameter that Bean has suggested for the open channel. There is just not much range when compared to the sensitivity of the overall system. I am going to go get a sanitary tee (or maybe a wide sweep 90 deg) and 1.5 in dia and try it out. This may give me a greater range for silent open channel flow while also getting me out of the vortex oscillation problem on startup.

Thanks.

 

[TheFishMan65]

T-Hunter,

I am having a little trouble picture what you have. But can you place something above the siphon pipe. Like a piece of glass. The vortex will only form if it can get air. If you can prevent the air from getting in, maybe it will behave properly. I hope I explained this well enough.

 

[cfsindorf]

Bean: I do not recall seeing a pic of your sump, does it have a refugium in it and if so how is it fed if the 3 drains go straight to the sump?

CFS

 

[BeanAnimal]

Sump build project:
http://beananimal.com/projects/acrylic-sump.aspx

Photo gallery:
http://beananimal.com/gallery/diy-75-gallon-acrylic-sump-gallery.aspx

Water test before permanent plumbing: Notice the air bubbles? That is fresh water with a MAG 9.5 before drilling for the external return pump. All (3) standpipes were setup as DURSOS. If it were saltwater, the entire chamber would be frothing with bubbles and that was just a mag 9.5!

The sump is high flow and has #50 or so of rock in it. It does not have a refugium. The refugium as above the display tank and is fed from a branch off of the return pump.

 

[PurdueMAN_08]

Okay i combed through the thread but couldnt find an answer to my question although I'm sure there is something close somewhere in the bazillion posts so I apologize if this has already been answered.
My question is this: How close to the bulkheads can the bottom of the horizontal internal overflow box be? Also how close can the top of the overflow box be to the rim of the tank (rimless) ? I have a 36"x37"x18" tank on order and can still modify it. They still haven't drilled it yet so any advice would be greatly appreciated! I'm thinking about having the bottom of the overflow box about 1.5" bellow the bulkheads and leave a 1" gap between the top of the overflow box and the rim of the tank. Also, should the pipes be about 1.5" below the top of the overflow box?

I hope this isn't confusing everyone. Thanks, Dan.

 

[BeanAnimal]

The box needs to be high enough to allow the down-turned elbows to be fitted onto the bulkheads and still flow.

The depth of water flowing over the wier depends on the rate of the flow vs the width of the wier. However, in most cases it should be less than 1/4" or so. I would leave a bit more than that to allow for high water during starting or abnormal operation. Set your emergency drain AT the same height or slight below the top edge of the wier, and the fail-safe air intake just slightly lower. The operational water level in the overflow box would be JUST below the air intake.

 

[IHfarmboy75]

If you are concerned about the siphon starting, then you can place the open channel standpipe bulkhead slightly higher (1/2" or so) than the siphon standpipe bulkhead.

Bean,
First, thank you for sharing such a wonderful design and putting up with the ignorance in the first part of the thread.
Ok, on to the question. I drilled all three of my holes before I got to this point in the thread so all of them are at the same height. I do have some play with my bulkheads since the holes are slightly larger so I could raise the open channel about 1/4" or so. Or are you saying to cut 1/2" off the street 90? Is this necessary to do at all? Are all three of your bulkheads the same height? Sorry for all the questions, I want to do it right the first time. 1000 Thanks!

 

[malcomm]

Thet MUST be air tight (other than the air inlet tubing for the open channel fail-safe).

Screw on caps with teflon tape or paste are specified in the plans

Can't get them here in Australia. We are a pretty back ward country at times.
Anyway used press on type caps with a coating of petroleum jelly to help them seal.
Works fine so far.

 

[malcomm]

Running external skimmer from the siphon line

Running external skimmer from the siphon line

Hi

Don't try this, it doesn't work well.

I teed of from my primary siphon line to feed an external skimmer. Did this before I received any answers to me questions as to wether it would work.

It doesn't. As the water level increases, the secondary line kicks in and gurgles in guts out. The primary does nothing. Nio water flow at all until everything backs up and teh emergency line is running full on, then it kicks in sometimes.

I believe this is due to turbulence at the T junction preventing a siphon starting for a while. By that time the secondary line has taken on the task instead.
You can adjust valves to get it to work but its not predictable and won't come back after a power outage.

cheers
Malcom

 

[malcomm]

Additional 4th siphon pipe? thoughts please.

Additional 4th siphon pipe? thoughts please.

Has anyone any thoughts on adding a 4th siphon pipe to run an external skimmer?
I'm wondering how this might screw up the balance of the primary siphon...
Also would it screw up the primary after a power outage?

cheers
Malcom

 

[buzbee_dallas]

Positioning of syphon bulkhead

Positioning of syphon bulkhead

I'm ready to drill the holes for the overflow bulkheads and I have a couple questions concerning their locations. My internal overflow is 6.5" inches deep and the top of the overflow is 1-1/2" below the top of tank glass. So total of 8" from overflow base to tank top.

From a few posts back, I'm using a 1-1/2" Hayward bulkhead with the threaded portion cut off. The bulkheads will be installed with the flange on the exterior of the tank. The interior portion now accepts a 1-1/4" pipe. So I'm using a 1-1/4" street ell fitting.

I've searched long and hard for a 1-1/2" - 1-1/4" reducing ell, but I don't think they are made. I even went to the Charlotte foundry web page, (they supply most of the PVC fittings around us in Dallas), and it doesn't appear they make any reducing ells greater than 1".

So that said:

1) Is it worthwhile to use a 1-1/4" - 1-1/2" increasing coupling to increase the intake surface area to avoid a vortex?

I'm also not clear on how far down the syphon intake should terminate. My basic understanding is that there should be at least 1/2" to 3/4" space above the overflow base and more is OK.

2) Is this correct?

Assuming that 1) I should add the coupling and 2) is correct:

Without any modifications, the 1-1/4" street ell and 1 1/4" to 1 1/2" coupling is 5" long from the center of the bulkhead. Adding 3/4" spacing to the bottom of the overflow says I should drill the bulkhead 5-3/4" above the bottom of the overflow. However, the bulkhead hole is 2 1/2". That would put the top of the bulkhead hole within an inch of the top of the tank glass.

Obviously this spacing won't work. I can probably cut down the ell and coupling fittings to shorten the length by 1-1/2" which would allow me to lower the bulkhead and have 1 hole diameter spacing from the tank top. But should I be messing with all this?

Just another lesson that you should get all plumbing fixtures before ordering the tank.

 

[afgun]

Why not just use a 1.25 sanitary tee and then increase (if you want) the downpipe to 1.5 ?

 

[buzbee_dallas]

Why not just use a 1.25 sanitary tee and then increase (if you want) the downpipe to 1.5 ?

My previous post is discussing the fittings inside the overflow. Outside the overflow I will be using 1.5" fittings.

 

[SkyFire]

Need some help

Need some help

HI I've read a lot of the thread, not all to be sure, it's very long.
I have a unique tank and need to know how to use this design for it with minimal invasion into the DT at least the part below the black glass band.
The tank is 113 gallons and measures 49"L x 22"W x 23.75"T approx. (I lost the paper that I jotted the actual measurements on).

The black glass band is 3 3/4" wide and the bottom of the 1"wide strip of glass at the top is 3 3/16" from the top of the shorter & wider piece of glass on the ends.

I was thinking that in order to do the design I'd need to make my overflow box 4 sided so it stopped before the side bracing and go below the black glass bracing FOr the bulk heads to be in it...or still stop before the side bracing and have the bottom of the box be even with even with the black band then have the bulkheads come under the overflow box and use elbows to bring them into the bottom of the box.

If I go from under the box then what how do I have the pipes be inside the box?

Here are pictures of the tank.
FTS

Looking down the length of the tank

Top Corner Detail

 

[SkyFire]

Anyone out there to help???
I've read all 40pages of the first thread so far about 20 pages of the second half of this thread.
Still need some ideas as to how to do this with my tank.