Many aquariums with dual overflows can be retrofitted to use a siphon-based Herbie Overflow. This post assumes a bit of understanding of the system so read through that if you’re just starting out. Having more than 2 pipes available allows for a secondary dry emergency line in some configurations. Those may be considered a Bean Overflow by some people.
It has been a common practice in the past for builders of these larger reef tanks to set them up with the “reef ready” design. Inside each overflow are two holes for bulkheads; one for the return, and the other for a single-pipe-drain. Some common brands are Marineland, Perfecto and a few others.
Some universal rules:
- If you have two pipes in the same overflow with different diameters, then always use the larger one as the emergency drain. You want it to have maximum capacity that matches or exceeds the capacity of the siphon drain.
- Don’t “Tee” any of the pipes with the Herbie for best results
- With a long tank that has 2 overflows, it becomes more important to make sure it sits on a level surface so that the overflows take on the same amount of water at each end.
Reasons to Update from a Single Drain System
Single-pipe-drains require no adjustment, but have several drawbacks. Air and water move through the drain at the same time, creating noise. There are many contraptions that attempt to quiet the drain with varying success (Durso, Stockman, Hofer etc.). If air moves down the pipe, there will be splashing down in the sump which can generate microbubbles or lead to salt creep. These drains also have only a fraction of the capacity of a siphon-based drain.
By converting the tank to use a siphon-based method like the Herbie or Bean method, the drains become silent and get more capacity to move a lot of water.
A note about “Reef-Ready” tanks
Reef-ready tanks may have small bulkhead openings compared to the size of the tank. Do your homework with flow rates and required turnover if you have a tank with anything less than 1″ bulkheads in the overflows.
These tanks often come with a return line running up through the overflow box. These are often changed into siphon standpipes with a Herbie conversion because they are often the smaller of the two in diameter.
Option 1: Independent Siphon/Emergency in each overflow
Due to the sheer volume of a tank that has two overflows – It’s often a really good idea to have a 2nd emergency line available.
With this setup, both overflows have both a siphon drain and emergency drain — like you would on a tank with only one overflow.
You may want to adjust one siphon so that it takes on less water, just enough to provide adequate surface skimming. The other siphon can then be used as the main point of adjustment, and can be the one that is easier for you to access.
With the amount of water that an single Herbie can move, having two means the siphon valves will be closed-off a considerable amount. This can mean finer adjustments are necessary.
Having two independent overflows can result in having to do too many fine adjustments which can be tedious. For this reason, some people choose to go a different route.
Option 2: Joining the two overflows so they act as one
If the two overflows can be connected with a “Tunnel” of sorts, then they will act as one overflow with two weirs. This is commonly known as a Balance Pipe. A pipe that spans behind the tank, passing through a bulkhead at the rear of each overflow. It could also be done inside the tank, but wouldn’t look very good unless covered with sand.
You will want the bulkheads for a Balance Pipe lower in the overflow so they are always submerged (below the siphon intake). Larger diameter pipe will allow water to equalize between the two overflows quickly. Strainers on each bulkhead opening will ensure that nothing gets in the pipe.
This setup allows for 2 pipes to be used as a typical siphon / emergency combo. The third pipe is used as the primary emergency and the fourth pipe can be used either as a secondary dry emergency, or as a return output running over the overflow wall into the tank.
Option 3: Only using one overflow and disabling the other one
If the diameter of the drains are of sufficient diameter — only one overflow may be enough.
Your main overflow would operate as a conventional Herbie drain setup with 2 standpipes (siphon and emergency).
In the unused overflow, one pipe is used as a dry secondary emergency, and the other as a return.
This method would makes the 2nd overflow dry. In order to keep it dry, you would have to slightly raise the level of the weir slightly. On this dry overflow water would only enter in the unlikely event that both the main siphon and emergency were completely blocked. If you don’t raise the weir on an unused overflow — it fills with water, and a chamber of nearly stagnant tank water is undesirable.
Option 4: What to Avoid – Teeing both siphon drains together
Some people wish to have only one drain line going to their sump, so they attempt to join the two Herbie siphons together. This is usually done below the tank under the bulkheads by using a “T” fitting.
This setup should be avoided.
You see, it is nearly impossible to keep the water level in two separate overflows balanced if they’re connected by the drain line. A siphon will always function as one unit, so the two intakes will affect each other no matter what. No configuration of valves or having equal lengths of pipe will change this.
The reason is that there are slight variations in flow from each siphon, like algae on the strainer or overflow teeth. These variations will always be present and changing the flow in the pipes over hours or days. One line will always affect the other if they connect in any way.
Gaining control over the water level in each overflow is only possible with individual siphons, or by connecting the two overflows with a Balance Pipe. A siphon must have it’s own independent valve and pipe extending down into the sump water to a chamber with a constant water level.
What about Teeing both Emergency drains together?
Never do that – Anything that lowers capacity of an emergency drain should be avoided at all costs. Ideally an emergency drain will go full-siphon, and this would be hindered by being Tee’d into another pipe. Siphons also can’t start as easily with with horizontal runs in the drain line.
Kenrick Venett says
What are your thoughts for joining the two siphons underneath the tank instead of a balance pipe between the overflows (inside or behind the tank). The underneath will be balance pipe with 45 elbows to minimize horizontal runs. Admittedly there will be a slight horizontal run when the two siphons come together at the tee but minimal. They should be pretty close to being balanced. If they are balanced then You can balance the pump with a single valve.
The siphon must be a totally separate pipe. A balance pipe that joins the two overflows must be completely independent. Without one, it is impossible to have the water level in both overflows the same. The problem is that the two overflows never draw in the same amount of water. Small variances between the two in overflow volume, weirs, or plumbing can cause this. One side draws in more water at any given time.
These little variances mean the water levels inside both overflows are different. “Pretty much balanced” isn’t going to help you, even if you lucked out and it worked like that (for a while). You can only adjust a siphon against an overflow that functions as one unit. Two overflows can function as one unit when you have a balance pipe – but unfortunately that’s the only time you can use a single valve and a T on your two siphon inlets.
Thanks for commenting – going to add some illustrations to this page to make it more clear.
Hello! Do you have any images, or a video example of the whole balance pipe practice? I’m having difficulty visualizing the way you explained it. Is it similar to the coast to coast weir pipe that mrrvbrown uses?
I will be adding 3D renders of each setup to the post very soon, so it will be easier to understand. The balance pipe is simply a pipe that joins both overflow boxes. Think of 2 buckets. If you were to drill the bottom of each, then connect them with a pipe, they would be a single vessel. If you were to fill one with water, the other would always have the same water level. I hope this helps.
Julius Taylor says
I’m converting my 150 gallon with dual Durso overflows to a Herbie setup. Rather than try to balance two drains or have a dry side, I’m running one of the old return lines back into its overflow. The water flows up through the weir. The other side has the main drain and emergency (converted from its return). I’ve removed the drain pipe from what is now the return box and just have its bulkhead closed off. I’m not sure if I will use a second emergency or just install a water level detector to stop the return pump.
I haven’t heard of that before but can’t see a reason why it wouldn’t work. I would probably not do it though because you can’t take advantage of the return line outlet as a source of flow in the tank.
orebro flughaven says
Thanks very much for your insightful articles. I’ve learned quite a bit. I’ll be taking delivery of a custom aquarium. This is to be used as a freshwater CO2 injected planted tank, and for years, I’ve only ever used closed loop systems so I’m completely unfamiliar with sumps. The tank is 180G and in the sump will be two independent identical DC return pumps each rated at 2000 GPH. My target turnover rate will be 10X so I assume each pump can be set at 50% to 70%. All holes and tubing are 1.5 inch dia. I don’t think that in reality the total return rate from the pumps will approach 1800 GPH but lets assume for the moment that it will
I’m intending to use option 1 in your article above, i.e. two external boxes each fitted with 1 siphon and 1 e-drain with all four lines independent.
I understand all the points you listed above as well as in your introductory Herbie article, but I haven’t seen any instructions as to how to get started configuring and testing, particularly for this configuration. I’m quite happy to have both siphons running some portion of the total return and to have both e-drains having some amount of trickle. I’m not interested in symmetry as I reckon that would be difficult to achieve. I’m also not in the camp that insists that an e-drain be dry, however it seems there may be some benefit in configuring the system so that it functionally approximate a Bean system. Again, however, it’s not really clear how to proceed.
Do I set both pumps to 100% with both valves full open and then begin closing one of the valves until that box’s e-drain starts to trickle?
Is it better to start with the intended pump setting first? Should I start with only one pump running?
Perhaps this is all old hat to reefers but it seems unclear to me exactly what the best procedure is for zooming in on valve configuration.
I could see myself turning valves and adjusting pump speeds endlessly without getting anywhere.
Any advice you could offer would be greatly appreciated.
Thanks for your well written and clear comment. The “10X rule” is one of those fish tank adages that that people like to repeat because it’s a nice round number. If the rule is followed, it will result in a loud, inefficient system in many cases. Return outlets also can’t provide the same kind of random flow that newer powerheads can create in the tank. Some of it has to do with personal preference, but if you read through Creating Flow in the Reef Tank you might start to agree.
For comparison, my 150 gal setup with a 40 gal sump currently uses a Danner Mag 7 pump. It pushes around 500gph with my 6′ foot of head height. A bit more flow would be nice, but then it would start to make more noise which I don’t want.
The main suggestion for you would be to only use one of the pumps.
Unfortunately there aren’t any tricks on how to start adjusting 2 siphon valves. Start with the valves fully open then start inching them closed alternating each one. If the valves are far apart you might get someone to help to man the other valve.
I have a 120G with dual corner overflows. Each overflow has a 1″ and 3/4″ bulkhead. Would it be possible to combine the plumbing for the siphon and emergency standpipes for each overflow, such that only one bulkhead is consumed. The herbie method seems superior to my current Durso, but I don’t want to lose any return bulkheads.
The siphon and emergency lines always need to be separate and discreet to work properly. There is no way around it unfortunately. This is why people convert their returns into drains so often.
I have a question for a possible hybrid herbie if possible.
I have a 150gallon reef ready aquarium. Has 2 corner weirs both durso and return lines come up this.
The durso drains are 1 and 1/4 inch reduced to 1inch that sets into the bulk head. The return lines are 3/4.
Could I keep both return lines as returns that are in the weirs.
Convert the left weir durso drain into a herbie full siphon and convert the right weir as the emergency?
What would be the pros and cons of this method?
Flow from the sump to the display would be very minimal but the tank will have more then enough flow from (2) gyres that will be in the tank.
You could only do it as you described it if you did the balance pipe method. That way, the 2 overflows would function as one vessel. The Pro – you could keep the return lines as is. The Con – might be a lot of work to drill new holes for a balance pipe with bulkheads.
With dual overflows, 2 holes each 1 inch and 3/4, could you use 1 1 inch as a herbie and the 3/4 with it emergency and then the opposite in the other overflow, 3/4 herbie and 1 inch emergency, return over the side
When you have 2 pipes in an overflow, using the larger pipe for the emergency is a best practice by design. Usually the siphon gets dialed back so it’s better to keep the larger of the 2 pipes in the overflow available as the open E drain to ensure enough capacity is always available.
Dude gmacreef you are the man! Another awesome page! I have been spending a lot of time reading all the good stuff you have on your page here. Went through a lot of the stuff on the Herbie setup and was happy to see the info for the dual overflows here. Just got a 125 for Christmas and I was at a loss after looking at all the initial reading and then seeing 2 corner boxes with 4 drains holes total. So my questions are
1) As long as I have the 4 drain lines separate (not going to tee anything) is it sufficient to run a single return to the tank over the back rim provided the pump can handle it?
2) regarding the drain lines I got the Eshopps RS-200 sump which has 2 bulkheads on the input side for the drains to come into. Is it okay to run the extra 2 drain lines right into the filter socks?
3) Hardware: My marineland came up with the hardware for 2 corner overflows that are setup for what I believe to be a Durso style. It would be better to do my own PVC and run a strainer on the siphon line and use a straight open exposed pipe for the emergency correct? As opposed to using the candy cane elbow for siphon or emergency?
4) is it okay for the siphon and E drain lines to be the same diameter pipe? Wasn’t sure if there would be a stronger siphon if one line had a bigger diameter. I understand if one is to be larger it should be the emergency
Sorry if that’s a boatload want to make sure I’m doing all of this right as its my first time plumbing a sump. Thank you for all the help!
Having two return lines with a pump for each would be best from a redundancy standpoint. Return pumps don’t fail very often if well maintained in my experience. Most people only run a single pump, but I have heard of some people running dual pump setups. I don’t think I would do it however just because of the extra noise etc. and the fact that a single return outlet creates more randomized flow in the tank than multiple smaller outlets.
The only thing to worry about with the drains is to make sure the siphon drain has it’s outlet submerged by 1″ under the water. The E-drain does not need to be submerged.
Some sumps have inlets for the drains to be plumbed into directly but you don’t have to use them. The E-Shopps one you described has drains that just dump water down through socks. This is fine for a Durso setup where air and water crash down through the pipe. With a Herbie, Most of the water will be draining through the siphon drain so you will need the drain submerged all the time. You may need a bit of a workaround if using that sump like moving the socks under the drain outlets.
For the standpipes inside the overflow, I would just plumb in new PVC pieces rather than trying to use the existing pipes.
It is definetely fine to have the E-drain and Siphon drain have pipe with the same diameter.
I guess I may have to do some rigging with the sump to make it all work, but I was kind of thinking that already. Thanks for the input on the returns also. I’m leaning towards just the single return line for sake of easiness but also pocketbook. Looking at the Jebao DCT 12000 and would rather not have to get a 2nd pump right away.
Another thing, if I’m going to get new pipe anyway would it be better to just go straight to 1.5 for this system?
Hey Gmacreef thanks for of your info its much appreciated. Is it possible to use two Herbie overflows ( 2 siphon tubes and 2 emerg tubes in total) in one single large overflow box? I would like my sump to filter just over 2000 GPH so I am thinking of using 1.5″ pipe.
Yes, it is possible. This would act the same as the “balance pipe” setup described in the article.
Doug Sheely says
What would be a recommendation for the size of the balance pipe between dual overflows on a 125 AGA Mega Flow overflow setup? If done this way couldn’t you use one 3/4 as the drain and 1″ as emergency drain and utilize the other 2 as returns located in each overflow?
A balance pipe is going to work best at a large diameter, so the water level in both overflows stays more even. I would say 1.5″ pipe would be about the minimum.
I probably would not recommend a balance pipe setup in your case.
You could run the setup as you described it, but you would be limited on what a safe return pump rate would be.
A 125gal will need at least 400GPH of turnover even as a low estimate. A single 3/4″ siphon drain just can’t move that much water.
Because of the small 3/4″ lines on your tank, all the pipes in the overflows should be drains.
You can then run a single return behind the tank and over the rim.
Matthew Preseau says
Thanks for your amazing advice. I have a 150 gallon tank with three holes drilled in the back, at the top. One each near the corners and One in three middle. They are drilled for 1″ plumbing. How would you plumb this tank? How should they bee used and what type of drain method should be used. My thought was all 3 for drains, one set higher as an e-drain.
Thanks in advance!
You could probably rig up some method that incorporates all 3 holes as drains, but you will need them to be contained in an overflow box if you want them to function as a drain system. You could build an internal coast-to-coast overflow if the holes allow, but these can take up a lot of room. It’s also hard to make them look good. If it were me, I would probably use the corner holes for returns or just cap them and do a Bean overflow box in the center of the rear wall.
Neil Belle says
Great articles as always. I’ll be setting up a 220g with an internal overflow drilled with two 1.5″ drains and 2 1″ returns. My sump has two drain inputs (one on each of the extreme left and right sides) with the return drawing flow from the sump’s center. Realizing you shouldn’t “T” a Herbie drain (to feed the sump from both sides) any other solutions you suggest? Should both 1.5″ act as full siphons with silencers on top (i.e. Durso or Maggie).
With most setups you want your drain outlets to go into a single area or chamber of the sump. From there it can flow into the skimmer chamber. Having drains on each end serves no purpose I know of – so I would change that.
With two 1.5″ drains and two 1″ returns you have some options. Assuming the returns are also in the overflow, one of them could be converted to a drain.
One of the 1″ returns could work as a siphon drain, and the other two 1.5″ pipes as your open channel and dry emergency lines. This would be a Bean Animal setup with 3 drains. With a tank over 200 gal I would always try to set up a Bean Overflow if you have the pipes available.
Also – just for clarity – Maggie Mufflers or Durso’s are not siphon methods. They are devices that are meant to prevent a siphon from starting in a single open drain standpipe. Here is a post going over each of these: Common Aquarium Overflows – Durso, Herbie and Bean Setups
Bruce Woolford says
Hello, I am setting up a 125 gallon saltwater tank, FOWLR for now but might switch to coral later. I have 2 eshopp prodigy L overflow box’s and 2 Eflux 6011 return pumps. My sump is a 40 gallon breader tank that will be in the basement on the other side of the house about 30’ away about 10’ lower then my display tank. My thoughts are to have the overflow box’s on the back wall one on the left and one on the right near the corners with the 2 returns 2’ apart from each other (my tank is 6’ long) on the back wall. I have (OCD) symmetry issues. Lol
Thanks for any input.
I don’t see any real problem with what you described. On a 125 gal tank, you could just use one of the Prodigy L overflow boxes and one return pump instead of two. That would cut the amount of pipes running between the tank and sump from 8 to 4. You would still be able to get over 5X turnover from the overflow and pump combo.
You might want to test how much flow you are getting on a single return line after pumping the distance all the way. I would just see how long it takes to fill a 5 gal bucket. With the return pump pumping such a far distance, testing the actual flow is a good idea. Flow charts can only tell you so much.
Bruce Woolford says
I really have enjoyed reading your articles and I truly appreciate your thoughts.
Bruce Woolford says
Hi, hope you are doing well. I’m still trying to work out my pluming and I have been rereading this article and the other post in it.
I see where you talk about a balance tube. To refresh my situation I have a 125gallon tank and I have 2 eshopps prodigy l overflow box’s. I want to use both box’s because I believe having 24” of wier is better than 12”. With that the 2 overflows have 3 1” drains in each box , how would it work if I used drain in each as a balance tube , 1 drain in each as an emergency drain and that leaves 2 drains 1 in each box could those be used as the main and secondary drain for the bean animal style system? I am looking for 600 gph of turnover, from what I have read 1 1” drain will handle that, do you agree?
Thanks for your help
Hi – What you have described certainly sounds like it would work – however most of the time people consider using a balance tube is when they are looking to retrofit an existing tank with 2 overflows. I don’t think I would recommend doing it to someone setting up a new tank with new overflow boxes. While the balance pipe method is an option to consider, it isn’t one that many people actually do. There are very few examples of this kind of setup online that people have shared.
In your case, 125 gallons just isn’t that big of a tank, even being 6′ long. There is minimal benefit to having 24″ of weir length vs 12″. The second overflow is just going to give you trouble because the siphon is going to have to split the 600 GPH between 2 pipes. Siphons get started faster and generally work better at the upper end of their capacity.
Also yes – 600 GPH is well within the limits of a single 1″ drain.
Bruce Woolford says
Any thoughts ???
Reef Keeper says
Great site(s) – very informative.
I have done a Herbie before with a 65 gallon reef-ready tank. Unfortunately, moved, broke the tank, and had to get a new one. The new tank has 3/4″ and a 1″ holes for drains. I am going to do another Herbie setup, with an external return over-the-back. Same 65 gallon size.
My question — do you think that a 3/4″ drain as the main siphon and the 1″ as the e-drain is sufficient? My return pump is max rated at 750 GPH (it’s variable DC) – I could scale it back so that I don’t have too much return flow. In my previous setup, I had a 1″ as the siphon, but the pump was never more than 40-60% capacity.
The 3/4″ main drain with a 1″ emergency is definitely sufficient. I currently have a 40 cube with 15 gal sump that has those same drain sizes. I have a Jebao DCQ-3500 that runs around 55% mostly because I want it silent. The drain can easily handle it at full power though so I think you are good.
I just set up my 180 with dual overflows. I ran both 1” siphons down at 1/2” per foot into a “y” then through a gate valve. Then I ran both emergency drains at the same 1/2” per foot into a “y” then into the sump directly. Every measurement is identical into the standpipes and “y’s”, tank is dead nuts level. From this article, my setup isn’t gonna work. How accurate is that.
It is not advisable to Tee any of the drains – by doing so you cut the capacity in half. Not good.
The emergency drains need to have at least the same capacity as the siphon lines.
On a Herbie drain, the Emergency drain needs to be able to go into siphon mode – which just can’t happen reliably if there are two inlets on the same pipe.
For the Siphon lines, they need to be separate, discreet pipes. This is the only configuration that works because each siphon line needs to be adjusted to the flow that is running in that particular overflow that it sits in.
Thank you for commenting.