Silent and Failsafe Overflow System

[asudavew]

Got my BA system up and running today. I have a 180 gallon tank, a separate 6o gallon frag tank, and a 75 gallon sump. Both tanks are plumbed BA style and drain into the same sump. Holy cow, they are quiet.!!

Just wanted to say thanks to Bean and Uncle.
Ingenious setup. Ingenious.

 

[uncleof6]

Greetings, This is my first post so be easy on me. Long story short, I'm in the process of having a 300g (96X24X30) acrylic built. Was going to go with 2 external builtin overflows each with 2 1.5" drains using maggie mufflers. That was before I got exposed to the Herbie and Bean overflow systems. Seems like the Bean is the way to go. Now the questions! I'm thinking one long external overflow will be better than two? What would the bulkhead size and number recommendations be? I'll be running two separate 45g reef sumps that will be joined together in the middle and "Tee'ed" with my pump which will be hitting approximately 2500gph into the tank

Single overflow, as it must be for this system to work properly. 1.5" bulkheads.

What is going to ruin your day is: two seperates sumps, joined together is not going to work, as planned—if at all. There are no if, ands or buts. This drain system cannot be split to two different locations, or it will not function properly. Looking at your plans, you would have to have two drain systems, discreet, and getting them tuned will make you crazy. IF you use two overflows, instead of one, both would have to be tuned identically, and the pump would have to draw identically from both sumps. That, realistically, isn't going to happen.

Quite honestly, I cannot think of a plausible logical reason to run dual sumps on ANY size tank. Do yourself a huge favor, and put out the bucks for a single sump large enough to suit this tank, in the 80 - 100 gallon range. The engineering hurdles you will encounter trying to use dual sumps, will ruin your love for reefing.

The only way a dual sump will work, is if you place one sump above the other, run your return from the bottom sump, drain the tank to the bottom sump, and power feed the upper sump with a branch from the tank return line, and drain that sump (through a real drain system) to the bottom sump. But, if you use the pump you are considering, you won't have enough pump for it, and you are planning an underpumped system to begin with.

 

[TankWater]

Thanks for the reply Uncle. I read an earlier post where advised someone else the same reference the 2 sumps so I was expecting that if you responded to this. . I have been running a 2 sump system (60G W/D & 30G R/S) in my 420G FOWLR (had the W/D before I put LR in tank) for the last 7 years without issue. A 1.5" equalizer line between the sumps kept the water level level in both sumps. However, all drains were coming from one big overflow ( 4 X 1.5" Dursos) and the max flowrate of course was much lower than I anticipate I will have with the Bean. I do agree that one sump would be the way to go in the Bean system if only one siphon drain is being used. I also see where 2 seperate overflows each with a Bean system in it could be difficult to tune and not the best way to go.. And just to be clear, even with one 7' long external overflow it is not a good ideal to run 2 Beans? I am starting to think I have 2 new sumps that I need to return.

 

[lightsaberx]

I would like to get anybody's insight on this overflow design before drilling the holes.
I'm following the design except that all the pipes will only be 1" all through out.
Got a 75 gallon tank, overflow box will be 12(L)x4(W)x4(H) inches in size.
Center of the holes will be drilled 3 1/4" from the top of the tank while i intend to keep my water level at 2".

Would gladly appreciate if you can advise any flaws or if it is ok to proceed drilling.

Thanks!

 

[BeanAnimal]

I don't understand the desire to have two sumps....

However for the sake of doing it, lets talk about the dynamics.

We have a single open channel and it drains into one of the sumps. We have (2) siphon standpipes, 1 draining into each sump.

The sumps are connected by a common pipe that has a TEE in the center that is connected to the return pump.

In general, the connector pipe will have to be of sufficient size to not only handle the flow (suction) of the return pump, but also to handle the mismatch of flow between the siphons feeding each pump. While this sounds simple the interaction between the sump levels is somewhat complex as water will have to flow in both directions at any given time.

With a smallish connector pipe the sump levels will oscillate as their flow and resulting head try to seek level but interact with the suction of the return pump. This will likely cause the siphon rate to oscillate as well.

The larger the connector pipe becomes, the less the system is likely to oscillate, but you still may run into issues with significant turbulence in front of the intake of the return pump resulting in cavitation.

As the connector pipe increases in size, the system starts to behave more like a common pool of water, not two pools connected by a pipe.

So, are two sumps connected by a common pipe doable? Yes... but with many possible pitfalls. I would seriously consider a single sump sized to meet your needs, or piping one sump as the intake and one sump as the discharge.

 

[TankWater]

Thanks for the response BeanAnimal.

My desire to have 2 sumps stems from entry/exit issues from my stand and the placement of the tank. I had a 6' sump that sustained a leak and I had two options. One was to empty the aquarium (420g) to get the sump out from the back of the stand and the other was to breakup the sump to remove it. I choose to break it up (was leaking anyway). My 8' tank is centered on a 14' wall that only leaves me 3' on each end to slide in a sump. By tilting I can get in a 4' sump max. I believe in getting the biggest sump you can fit/use in your system as possible, therefore, I went with two sumps. I guess its the fear of another leak that ultimately leads to me using two sumps instead of one.

Please correct me if I'm wrong, but with the BeanAnimal system and 1.5" PVC I will get way more flow that my previous plan of using 4 1.5" standpipe drains. But if I reduce the 1.5" to 1" bulkhead fitting at the sump that would reduce flow and subsequently be a bad ideal. As I understand, you never want to "T" the siphon line so splitting the 1.5" into 2 1" pipes is bad. Now what if I were to split the 1.5" via a "WYE" would that work?. I ask because my current sump I just purchased has two 1" bulkhead inputs.

 

[535freak]

could you run your drains to one small sump that holds your filter socks then split to your 2 main sumps?

 

[uncleof6]

could you run your drains to one small sump that holds your filter socks then split to your 2 main sumps?

No, because you will end up with a double gravity feed that will never balance properly: flood time.

 

[marc111]

Just a comment on using the beananimal system in two separate overflow boxes. I have one up and running and it works just fine. It is very stable and when the return pump is turned off and restarted it re-establishes itself completely reliably. I found that the two boxes were almost independent from an adjustment standpoint. Especially as you approach the running point. Just get each one close and then adjust while watching how much flow is in the secondary pipe. Once it is down to a small flow you are set.

Mark

 

[marc111]

Beananimal, a question:

I am finding as many have commented that things are very stable and I have about a 1" waterfall into my external overflow box with your system as constructed.

I would like to reduce this to about 1/2 inch. It seems with this system design that once you have the piping in place the overflow box level is set.

It seems to me that with this design it is the height of the second (small flow) elbow that sets the overflow water level.

I am thinking that to raise the level a bit more I should raise the second down-turned elbow ( the one with the air hose) so that running water over that weir would occur at a higher level as I adjust for the full siphon point via my full syphon gate valve.

Your thoughts?

Thanks,
Mark

 

[BeanAnimal]

Marc raising the weir height of the open channel will server to adjust the operating level of the system. You can think of it as the spillway of a dam.

The system (as published) is 4' wide and the water (even at 3500gph) sheets over the weir. The same flow over a small box will form a waterfall.

You don't want a hole within 2 diameters of the top edge of the glass, so it may mean a taller overflow box so that the siphon can be moved down (as opposed to the OC being moved up).

 

[marc111]

Thanks for the feedback. In my case the overflow is an external box attached to a plywood tank and the opening plus return volume sets the water level in the tank. I will try slightly raising the small flow elbow .

Thanks,
Mark

 

[marc111]

That did it. raising the small flow elbo allowed me to raise the overall warter level the desired amount and lessen the flow on the small flow pipe. The dual overflow system is now even more stable.

Thanks,
Mark

 

[535freak]

how many gph can you get through 1.5 pipe

 

[BeanAnimal]

that depends on the type of flow through the pipe (full of water, or mixed with air, etc). The fluid in a full pipe under gravity flow will behave according to Bernoulli's law.

I have built a calculator here:

http://www.beananimal.com/articles/hydraulics-for-the-aquarist.aspx

That estimates flow using the equations Bernoulli derived.

 

[535freak]

I meant with a full siphon how many gph in 1.5 pipe

 

[535freak]

tried the calculator and at 30" it would be 4200 gph for 1.5 pipe but what if you had another 8' horizontal to the sump

 

[Kyle918]

I am nearly complete with my BA. I just need to attach the overflow to the inside of the tank. My question is, how much clearance is needed from the bottom of the overflow to the down turned pipes? I want the least about of intrusion from the overflow into the tank.

Currently the overflow I have made from glass will yield about a half inch of clearance. Only once I held it in place I thought maybe that isn't enough to allow enough water to flow and keep a siphon. I can make another overflow no problem so please advise if that is enough clearance.

 

[uncleof6]

tried the calculator and at 30" it would be 4200 gph for 1.5 pipe but what if you had another 8' horizontal to the sump

That is estimated 4200 gph max theoretical flow... not taking into account ambient pressure, temperature, blah blah, and friction loss in the pipe. Your flow rate will be lower, due to the pipe.

One of the quirks with 'siphons' is horizontal runs can and do cause starting issues. Air becomes trapped along the horizontal run, and it air locks. Similar to how dursos behave, but not as severe. What happens is the open channel takes more flow than it should, and the siphon line never fully starts, because it cannot purge all the air.

With this system, or any drain system for that matter, horizontal runs should be avoided. Ideally, the drain should go straight down, though that is seldom possible. The angle should be kept @ 45° down from horizontal or more. Less can work, but really...using standard fittings (and not tweaking the joints) you only have three choices: 22.5°, 45°, or straight down. If you know how to heat bend pvc, then you can get a bit more creative.

Honestly, if you are planning a sump 8' horizontally away, it would be best to re-evaluate your plans...I really don't see much point in running remote sumps. Fish rooms are fun to plan, but in reality, unless you are doing research, they are a waste of time--unless directly behind or below the tank, and I don't much care for below either.

 

[uncleof6]

I am nearly complete with my BA. I just need to attach the overflow to the inside of the tank. My question is, how much clearance is needed from the bottom of the overflow to the down turned pipes? I want the least about of intrusion from the overflow into the tank.

Currently the overflow I have made from glass will yield about a half inch of clearance. Only once I held it in place I thought maybe that isn't enough to allow enough water to flow and keep a siphon. I can make another overflow no problem so please advise if that is enough clearance.

I am not liking 1/2" clearance. 3/4" or even 1" would be more comfortable.

Function comes before aesthetics; I find this "minimizing intrusion" trend to be a bit silly. I understand it, but function comes first. While I am at it, the back to front width needs to be wide enough to get your hand in and R & R the elbows.