There are also a few options with Herbie style overflows, I personally prefer to use a standpipe as the secondary drain as appose to a straight pipe. This will allow a little more freedom in adjustment and give more tolerance meaning you won't have to adjust the valve as often to keep the system quite. Here's a diagram I made a while ago to illustrate this:

http://i84.photobucket.com/albums/k3...icplumbing.jpg
http://i84.photobucket.com/albums/k3.../trimetric.jpg
http://i84.photobucket.com/albums/k3...frontnoted.jpg

I would suggest you don't tee the two drains together at the sump as shown though, keep them separate for best results. You can also use a stock-man style standpipe rather than an HGB.

HTH

Could I get a couple more detailed pictures?

Also do you have to drill the holes in the bottom of the tank to do the herbie system?

how do you make the pumbing stable ?

In Reefjunkie's build, there some pictures of a Herbie with the bulkheads on the side.

I see one problem with your drawing Sphelps(other than its far more complicated than it needs to be)....with the two drains merging into one, the only way to tell if something has clogged the primary drain is if you visually inspect it....if you run each individually, the primary is plumbed down below the water line of the sump(making it silent) and the emergency is plumbed just above the water line so you can hear it trickle if something has clogged the primary.

I prefer the BeanAnimal overflow which is basically a Herbie with an extra hole/pipe:

http://www.beananimal.com/projects/s...ow-system.aspx

You can apply the same principles in the BeanAnimal for a bottom drilled tank or, as in my case, an external permanently mounted overflow box (not a siphon overflow).

All of these systems ave a multitude of ways to doing them, you can actually do a Beananimal or herbie style through just one bulkhead if you have the tools to do it and the ability to figure it all out.

Pick which one you feel comfortable with, learn how it works first before you mess with it.

Like I said you have options and there are many ways to do these types of overflows. However everything in there serves a purpose, for example:

The siphon tube takes water from the base of the overflow preventing too much build up which is common with overflow boxes and the hole breaks the siphon during a power cut or shut off which prevents the entire overflow box from draining.

The standpipe skims the surface water preventing surface scum from being trapped in the box. The standpipe also allows more tolerance, so if your flow changes slightly over time it won't effect the noise level. This is a really nice feature, less tinkering is always good especially if you're away for a while and have someone watching the tank. The last thing you want is to explain to someone how to adjust your drain to match your flow :confused: and you won't get the panic phone call becuase the tank is making crazy noises. The standpipe also allows you to use a ball valve instead of a gate valve which are easier to find and significantly cheaper.

The reduction in pipe size in the return also serves a very important role, it prevents a pressure drop which can in some cases cause oxygen to liberate from the water creating micro bubbles.

Other than that I don't see the complication, but we all see things differently and we should do things that make sense to us within reason. If one chooses to omit certain parts or do things completely different that's there choice. My intent was only to show an example of another alternative, like I said the drawing was made for someone else but works well as a visual add for other people. I personally wouldn't recommend a Herbie to someone just starting out becuase it is a more complicated system which is why I never mentioned it in the first place.

Also about the tee in the drain I already mentioned to omit that:
The reasoning however isn't related to what you said but rather to noise, if tee'd them together the noise from the primary will echo up the secondary creating a gurgling noise which will be hard to eliminate. I realized this after I made the drawing and didn't feel it was necessary to change it as I always note to omit that part when I post it.
If you did tee the lines together you would certainly be able to tell if the primary was clogged as you would clearly see more flow going though the standpipe which will also make a little more noise but at least it wouldn't sound like a toilet exploding :wink:

Doing this through one bulkhead would be a bad idea. The reason for the redundancy is to avoid potential disaster. For example, my BeanAnimal overflow saved my a$$ the other day: I had several nassarius snails apparently climb into my overflow and die in the main siphon pipe. If I had one bulkhead and they managed to get lodged in the pipe somewhere at a point either just before the bulkhead (presumably where the network of siphons and emergency drains converge to enter a single bulkhead in your proposed one-bulkhead suggestion) or in the pipe on the other side of the bulkhead the redundancy of the extra overflows would have been moot and I would have had a wet floor.

I think you have misunderstood exactly what I mean, I have no intention of running all the pipes into one drain, all feeds go independently to the sump, I think I know how to keep the floor dry, Beans super safe system was designed for precisely that reason, although a Herbie is good, the extra fail safe is enough to keep his marriage from coming to a wet end.

Could you explain or, preferably, show a diagram displaying how you would plumb a BeanAnimal overflow with a single bulkhead? That certainly would have been easier to do when I was building my tank and external overflow.