Pipe sizing confusion on herbie style plumbing

Ethan073

New member
I'm planning to run two tanks on a shared sump with flow supplied to both tanks from a single return pump. I want to apply the herbie style overflow to both tanks, but with the first tank's main siphon plumbed to the IN of the second tank as it's primary feed.

I've read many threads & articles on this as well as BeanAnimal's threads on his variation, but I'm still stumped on what pipe diameter will be ideal for my application, especially with my unconventional routing between multiple tanks with some diagonal drops rather than vertical - I'm assuming this could make a significant impact??

Any help in figuring this out would be very much appreciated, I've never done this before!

Here are the plumbing routing details...
http://tinypic.com/r/21oykbs/5
Green: Full Siphon, 75g to 60g, ~1.5' pipe length, ~6" vertical drop, two 90° elbows and one ball valve
Purple: Open Channel, 75 to sump, ~3.5' pipe length, ~3' vertical drop, three 90° elbows
Orange: Open Channel, 60g to sump, ~3' pipe length, ~2' vertical drop, three 90° elbows
Pink: Full Siphon, 60g to sump, ~2.5' pipe length, ~1.5' vertical drop, three 90° elbows and one ball valve
Blue: Return Line, powered by Maxi Jet 3000 utility pump with ~500gph @ 4' of head pressure


Hopefully I've included more than enough info and not too little!
 
Last edited:

Gorgok

New member
It would be so much easier to split the return pump with gate valves to both tanks, and just drain each into the sump... Especially since you are not going a full bean.

With the herbies you would have to tune two siphons to be perfectly in sync between two very different drops, or one will flood the other or always be noisy and sucking air. If you run the dry emergency as an open channel you do make it much easier to tune, but you have no true backup in this case and have doubled the risk of failure by forcing all water to drain twice.

Also, you have a massive restriction in the drawing on the first siphon (the loc line i assume)... I don't think that is safe at all here, and probably won't function at all as you expect.
 

Ethan073

New member
Gorgok, splitting the return line to both tanks individually is a better idea. I'll go that route. And Ty for pointing out the loc-line error on the first siphon.

Jimmy, if I route the plumbing from the 60g straight down and then run it over to the sump (making an L shape, rather than a \ shape) would that alleviate any concern over the siphon restarting?


Also, I would like for my plumbing to be capable of running half the flow split from the return but also be capable of handling the full 500gph just to be safe. If I used plumbing large enough to suit the full 500gph, would that be too large of a pipe to siphon 250gph or would there be no problem there?
 
Last edited:

jimmyj7090

aka John K
Jimmy, if I route the plumbing from the 60g straight down and then run it over to the sump (making an L shape, rather than a \ shape) would that alleviate any concern over the siphon restarting?


Also, I would like for my plumbing to be capable of running half the flow split from the return but also be capable of handling the full 500gph just to be safe. If I used plumbing large enough to suit the full 500gph, would that be too large of a pipe to siphon 250gph or would there be no problem there?

It's hard to say for sure without setting it up and trying it.

The problem with way oversizing the drain pipe is mainly that you'd have to have that big gate valve >%90 closed which would most likely make it difficult to tune, and tuning is key with herbie drains (gate valves are much easier to tune in the middle of their range and not so much on the extreme ends of their range IME).

For your application 1" or even 3/4" will be totally adequate. If it were me, I'd probably go with 1" even though that's also pretty oversized for what you're planning, but maybe reduce it to 3/4" at the valve.

It's not that you can't oversize the drain, but @500gph using 1.5" pipe would be a lot like using a fire hose for a drinking straw :)
 

uncleof6

New member
Gorgok, splitting the return line to both tanks individually is a better idea. I'll go that route. And Ty for pointing out the loc-line error on the first siphon.

Jimmy, if I route the plumbing from the 60g straight down and then run it over to the sump (making an L shape, rather than a \ shape) would that alleviate any concern over the siphon restarting?


Also, I would like for my plumbing to be capable of running half the flow split from the return but also be capable of handling the full 500gph just to be safe. If I used plumbing large enough to suit the full 500gph, would that be too large of a pipe to siphon 250gph or would there be no problem there?

No it won't solve anything, rather it will create a horizontal run, that is known to cause air locking in the siphon line, which will prevent it from starting properly. For some reason, jimmy got this reversed...must have needed some more coffee, or maybe some bacon... ;)
 

Ethan073

New member
So the \ shape drain is the better way to go then.

It sounds as though maybe going full bean with 3/4" full siphon & open channels with 1" emergency drains is my best bet here?
 

jimmyj7090

aka John K
No it won't solve anything, rather it will create a horizontal run, that is known to cause air locking in the siphon line, which will prevent it from starting properly. For some reason, jimmy got this reversed...must have needed some more coffee, or maybe some bacon... ;)

Coffee yes, bacon no.

I've never tinkered with a horizontal run on a siphon so I wasn't commenting on that, but I certainly wouldn't suggest it. I have seen a situation where an angled drop kept the siphon from working so I was cautioning against that :)
 

uncleof6

New member
So the \ shape drain is the better way to go then.

It sounds as though maybe going full bean with 3/4" full siphon & open channels with 1" emergency drains is my best bet here?

No again. The smallest practical size for any drain is 1". 3/4" is too restrictive, (too much friction loss) and too easy to plug. Even 1" is a bit shakey, when it comes to the open channel, and you would be better off using 1.25" for the open channel as it will be easier to keep quiet.

In terms of the geometry of the drain system, I have never (many many iterations) seen a 45° geometry pop a start up problem. That said, between 0° and up to 44°, your mileage will vary, depending on the actual angle; the lower the angle, the better the odds of a start failure. There are a few reasons for start failures with the BA system, but it is limited to just a few. We say this system works as designed, and "as designed" uses 1" bulkheads, 1.5" pipe, with a 45° geometry.

What you can expect from "as designed" is ~ 1500 gph with a 2 foot drop, and perhaps 1800 - 1900 gph or so with a 3' drop. However, the bandwidth is very wide, and will not show any issues with your lower flow rate. With 1" bulkheads/pipe, you can expect ~ 1200 or so with a 2' drop. The bulkhead size is the limiting factor, the pipe size is just "how much" friction loss will bring the capacity down.
 

Ethan073

New member
Whoo! There's clearly a lot more to this than I understand. I can't thank you guys enough for the help!

Should this be adequate? All of these with 1" bulkheads, with channel & SOS at 1.25" pipe and siphon with 1" pipe?
The diagonal from the left side tank will be steeper than 45°, at a guess somewhere around 35°.

2a7fk1g.jpg
 

uncleof6

New member
Should work. I would be careful pulling the angle down to 35° though. This puts stress on the fitting joins, throughout the whole system. It could cause a problem or not.
 
Top