Bean and Herbie Overflow question

[Coffee with Mango]

I am considering buying a 120g with two one-inch drains and setting up a Herbie overflow. While comparing the Herbie with the Bean method, the resources I was reviewing have the Herbie full siphon drain pointed straight up with a screen on top. The Bean full siphon drain, however, is an inverted U (opening faces down). What is the reason for the downward facing opening on the full siphon drain in the Bean overflow method?

Thanks in advance.

 

[JohnK]

Herbie's are fine with the downturned elbow as well.

The down pointed elbow will reduce any tendency for the drain to suck in small bubbles created by the small drop between the surface in the display and the surface in the overflow box.

 

[Coffee with Mango]

Herbie's are fine with the downturned elbow as well.

The down pointed elbow will reduce any tendency for the drain to suck in small bubbles created by the small drop between the surface in the display and the surface in the overflow box.

That makes sense.

Another question: what gets the siphon started with the downward facing elbow initially? Why do I see videos of these types of downward facing drains (in the bean overflows, for example) magically restarting the siphon after interruptions? With the upward facing pipe, it's obvious that gravity gets the water flow going and when the air is purged from the pipe it goes full siphon. It is not so obvious to me how it gets started with the elbow.

Thanks in advance, again.

 

[Jim Tansey]

As the water rises it comes up to the horizontal portion of the elbow and falls do to gravity, same as the up turned elbow no different, except the water flows at the neck level as opposed to the upturned end.

Jim

 

[reefstarter]

Can I add a question ? I have a 3/4 and 1 inch spot for a her i.e. Thinking set water in flow to not overwhelm the 3/4 and dial the one inch in as main drain sorry for the hijack lol

 

[Jim Tansey]

Which one you use for the main drain is not important but they BOTH must be capable of handling the required flow WITHOUT the aid of the other.

Jim

 

[Coffee with Mango]

Okay. So I have one 1" that I can run full siphon, and the second 1" can be a "slightly wet" emergency drain. Assuming I have to dial back the drain in the full siphon with a gate valve under normal operation, and if I leave the emergency drain unchecked, as long as the emergency drain can establish a siphon if the original gets clogged I'm probably okay. It's the "probably" that worries me.

 

[JohnK]

I would always use the smaller hole for the siphon, but as Jim said as long as both can handle the full flow it really doesnt matter.

On adjustment, ideally you keep the emergency dry, but that requires fairly frequent slight adjustments.

 

[Jim Tansey]

Ya... My emergency will often have a slight trickle.

Jim

 

[JohnK]

No harm in that really. I was sold on the thinking that you should always have 100% back up capacity, but im sure 98% is plenty about 99.99999% of the time.

 

[Coffee with Mango]

No harm in that really. I was sold on the thinking that you should always have 100% back up capacity, but im sure 98% is plenty about 99.99999% of the time.

But I think the emergency will actually have more capacity than the primary siphon drain if the primary siphon drain is normally dialed back with a valve and the emergency is wide open (both 1" pipes). Even if there is some regular small flow in the emergency drain, I would think it would still have greater capacity than the dialed back siphon -- once it becomes a siphon itself in the event of an emergency.

With the two drains drilled in the bottom of the tank in a traditional overflow, I could have the main siphon say 7" below the weir (tank water level) and the emergency drain 6" below. If I could keep the normal water level in the overflow at about 5.9" inches below the weir -- I think that would work? If the primary clogged then the water would rise and hopefully the emergency drain being submerged so much would convert to a full siphon. And once converted, it would actually have greater capacity than the original dialed-back primary siphon because it wouldn't be dialed back with a valve.