Herbie size for 150G

[savanyo]

I'm designing a new 150G tank and I want it to be as silent as possible to make the wife happy. I'm planning to use a singe overflow with a herbie drain and would like it to handle 3-5x turn over per hour (450-750 GPH). So i wanted to ask for feedback on plunging size.

Current thinking is use:
- 1" return, which is probably overkill for desired flow rate
- 1-1/4" siphon drain
- 1-1/4" emergency/trickle drain

Thoughts?

-John

 

[sleepydoc]

If you're in the design phase, consider a Bean animal drain - much easier to maintain and keep tuned for silence.

For maximum safety, a Herbie needs to have a dry emergency. If the 2nd drain pipe is handling flow, think of what happens if/when it gets occluded.

1" can handle your proposed flow, but you may want to upsize the piping to minimize head pressure and efficiency of your return pump. You can check head loss here

 

[ca1ore]

I'll be honest, I run herbie drains in a non 'traditional' way in that I don't worry about maintaining the dry backup dry. Consequently I'm an advocate of having as big a backup as is possible. For the siphon, at your desired flow rates, even a 3/4" would likely suffice, however, 1" is probably a better choice (particularly if you ever decide to up the flow). As to the return, I think 1" is more than enough. You're likely looking at a pump with 3/4" input/output anyhow. Lastly, I put screens on all my drain pipes. Requires a bit more maintenance to clean periodically, but it prevents them from becoming quickly blocked by something like an errant snail or fish carcas.

 

[savanyo]

I'll be honest, I run herbie drains in a non 'traditional' way in that I don't worry about maintaining the dry backup dry. Consequently I'm an advocate of having as big a backup as is possible. For the siphon, at your desired flow rates, even a 3/4" would likely suffice, however, 1" is probably a better choice (particularly if you ever decide to up the flow). Lastly, I put screens on all my drain pipes. Requires a bit more maintenance to clean periodically, but it prevents them from becoming quickly blocked by something like an errant snail or fish carcas.

This is similar to my thinking.

I'm also planning to run the hebie in a non-traditional way. I want to have most of the flow run through the siphon, but have a small amount running through the emergency with a durso top so it is quiet. A design parameter is that either drain could get 100% flow if the other drain is is blocked.

I agree a 1" siphon can handle the desired flow. But the emergency/durso should be bigger at least 1-1/4. Since the emergency/durso has to be at least 1-1/4, I was thinking I can bump up the siphon to also be 1-1/4 without any significant penalty. Although I think if the siphon line has too large a diameter relative to the flow, the system could have a problem restarting siphon on startup because it is harder to clear out the air in the line.

The major uncertainty I have is whether I should bump the emergency/durso size up to 1-1/2". The only reason I am reluctant is that it means I would need to make the overflow box deeper to fit the larger bulkhead. The depth of the overflow box is controlled by the size of the largest bulkhead.

So I guess this boils down to whether or not a 1-1/4" emergency/durso can handle all of the desired flow (450-750 GPH) if the siphon line is completely blocked.

I agree with putting screens on all drains. I will put a tee or cross at the end of each drain with 1/4" mesh screen glued to the openings.

Thanks
John

 

[savanyo]

A design parameter is that either drain could get 100% flow if the other drain is is blocked.

On second thought the above is false. If the valve on the siphon is adjusted so that some flow is always going through the emergency with durso top, then the siphon can't handle all the flow since the valve is restricting the flow.

So let me restate: a design parameter is that the emergency drain with durso top must be able to handle all flow if siphon drain is completely blocked, but not vice versa.

Options are:
A: 1" siphon + 1-1/4" emergency/durso
B: 1" siphon + 1-1/2" emergency/durso
C: 1-1/4" siphon + 1-1/4" emergency/durso
D: 1-1/4" siphon + 1-1/2" emergency/durso

All above with 1" return (for convenience to hook up to 1" pump).

-John

 

[ca1ore]

The larger siphon will gain you nothing because you end up closing it down with the gate valve. You'll simply spend more on the piping and valve.

 

[savanyo]

The larger siphon will gain you nothing because you end up closing it down with the gate valve. You'll simply spend more on the piping and valve.

Thanks and agree. From on-line calculator, a 1" siphon drain at 42" head can handle 2205 GPH.

So I'm inclined to go with:
A: 1" siphon + 1-1/4" emergency/durso + 1" return.

Then I can keep the overflow box relatively shallow, about 5.5" deep trapezoid shape (width 18-10").

 

[uncleof6]

I'll be honest, I run herbie drains in a non 'traditional' way in that I don't worry about maintaining the dry backup dry. Consequently I'm an advocate of having as big a backup as is possible. For the siphon, at your desired flow rates, even a 3/4" would likely suffice, however, 1" is probably a better choice (particularly if you ever decide to up the flow). As to the return, I think 1" is more than enough. You're likely looking at a pump with 3/4" input/output anyhow. Lastly, I put screens on all my drain pipes. Requires a bit more maintenance to clean periodically, but it prevents them from becoming quickly blocked by something like an errant snail or fish carcas.

People do it, but despite any anecdote associated with the practice, it does not make the practice safe or advisable. It merely means that folks do it with a careless disregard to the potential flood issues that can come with it. Those with considerably more experience don't dare flirt with the odds. We learned the hard way. We merely try to save others from having to learn the hard way.

 

[ca1ore]

People do it, but despite any anecdote associated with the practice, it does not make the practice safe or advisable. It merely means that folks do it with a careless disregard to the potential flood issues that can come with it. Those with considerably more experience don't dare flirt with the odds. We learned the hard way. We merely try to save others from having to learn the hard way.

But anecdotes are all we have; unless of course you are privy to long-term data that disproves my 'reckless' approach. I am quite comfortable that the approach I have been using for, gee let's see, 25 years has long since dispelled the myth (for me, at least) that maintaining a fully dry backup is necessary. Perhaps with a bit more experience, you'll come to a similar conclusion :lol:

Lot's of people implement their drains in an inadvisable manner, and get a flood for their troubles. Maybe my approach carries a slightly higher level of risk, but I've operated multiple tanks this way and have yet to have a drain failure. That's 10 data points .... er, anecdotes.

 

[uncleof6]

But anecdotes are all we have; unless of course you are privy to long-term data that disproves my 'reckless' approach. I am quite comfortable that the approach I have been using for, gee let's see, 25 years has long since dispelled the myth (for me, at least) that maintaining a fully dry backup is necessary. Perhaps with a bit more experience, you'll come to a similar conclusion :lol:

Lot's of people implement their drains in an inadvisable manner, and get a flood for their troubles. Maybe my approach carries a slightly higher level of risk, but I've operated multiple tanks this way and have yet to have a drain failure. That's 10 data points .... er, anecdotes.

The data is called common sense! If your wet secondary slows, even a small amount, the siphon will not compensate due to the restriction by the valve. The water level will rise, and the water will end up on your floor.

25 years experience running a siphon with a wet secondary is a bit hard to believe. The "Herbie" has only been in existence since 2004. There are another 14 years to go before hitting 25 years. No one started running a wet secondary till some time after Bean published his design, so that shortens the amount of possible time. Those of us that were running siphons 20 - 25 years ago, knew the risks, without an emergency (which by default was dry, as no one thought to run wet secondaries till after Bean published,) and found them to be unacceptable.

It is fine if you wish to disregard the safety warnings that Herbie, myself, Bean, and others have posted. That is fine. But when posting about it, the fact that what you are doing is at the expense of safety will be brought up. I have had several clogged drain lines over the years. It is my desire to prevent others from having floods, because the safety has been disregarded. Hopefully, so they don't have to learn the hard way. Because I am the one that usually says it, the results will be the same. See previous posts.

Perhaps some think I dream this stuff up?

Bean:

"That brings us to the system that I published. If you read the Herbie thread, I was not (at all) thrilled with the dynamics of the tuned siphon unless it was backed up by a dry emergency (at the very least). The problem with that system is the limited bandwidth and need for constant adjustment. The wet secondary fixes this but at the expense of safety."

"This system MUST use the (3) standpipes that are described above. The emergency standpipe is a CRITICAL part of this design. Omitting the emergency standpipe is asking for a flood!" (speaking of the dry emergency.)

or maybe Sleepydoc:

"The problem actually arises when the secondary train (sic) unexpectedly clogs. By design, you have the primary throttled back so it can't quite handle everything and you depend on the secondary to handle the excess. If it should clog for any reason, the excess will build up and cause a flood."

or maybe even Herbie himself?

"So I came up with a VERY IMPORTANT SAFETY FEATURE!!!!! I took out the rigid pump output line inside the overflow box and set it up as a higher (just below the intake overflow box "teeth") safety return plumbed directly to the sump, above the water a little bit. It should be empty at all times unless something is out of wack with the main return line!"

Again, the fact that people do it, does not make it safe, and it does not make it advisable. It simply means that people do it.

 

[savanyo]

If your wet secondary slows, even a small amount, the siphon will not compensate due to the restriction by the valve. The water level will rise, and the water will end up on your floor.

Safety is not binary (safe vs unsafe). There is always a spectrum of risk.

Running a Herbie with a wet secondary is no less safe than using a single durso drain. I agree if wet secondary is obstructed, then you will get a flood the same as if a single drain system gets obstructed. Therefore protecting the wet secondary is equally important for safety as in a single drain system.

I have been running a reef tank for 12 years using a single durso dain and I have never ever had an flood. The reason I have never had a flood is that I protect the drain inlet with great care. Firstly, I attach 2 PVC Tees to the bottom of the durso inlet, so this provide 3 separate inlets greatly reducing the suction power at each of the 3 inlets. (I derived this concept from regulations in most cities that now require 2 drains at the bottom of all swimming pools and spas to prevent "drain entrapment" where kids get suctioned to a drain and drown). If a big Tang got in the overflow, it will not be able to block off the drain with it's body. The suction would be so small, it would likely fall to the bottom of the overflow. Secondly, each inlet is protected with a 1/4" mesh plastic screen glued in place, preventing snails and smaller items from getting in the drain. Presto. Super safe drain.

 

[iced98lx]

The self adjusting portion of the BA or a wet secondary on a herbie are very nice, and worth the price of admission and will provide consistent silence.

While I agree slowing a wet secondary and causing a flood is a concern, my secondary runs VERY slowly (I've tuned it as slow as possible) and it would take a large blockage (nearly 100%) to make it so that it caused a flood. Even a rise in tank water would result in a flooded air line and whatever portion of that pipe is left would go siphon. I value the dry backup a lot, and wouldn't be without it but I will be surprised to see it get used with the way things are set up. Beyond that I have a float switch that will kill the return pump should the water level rise to a point I don't want it.

It's about managing and mitigating risk, the optimal design (clearly some believe that to be the BA with very rigid definitions around it) goes a long long way, but the world is full of compromised design. If you have the opportunity adding the safety net of a third completely dry channel is very nice.