Herbie drain question

[Sgt Jonny Cat]

Hello everyone, I'm researching the Herbie drain in my 150 gallon tank build and I read that the main siphon drain needs to be under at least 6 inches of water. I plan on having a 55 gallon sump, and was thinking 6 inches of water is ALOT to drain when the return pump is shut off. ( I calculate approximately 30 gallons of water going into my sump.) Is this correct? Or am I missing something? Does the main siphon drain need to be that deep?

Thanks again everyone...

 

[ramseynb]

I can confirm that what you read is incorrect. I have an Eshopps overflow that I added to my tank that has a Herbie overflow system and there's no way it's 6" of water. Maybe three inches. Your valve on your main drain will allow you to adjust the water level and find a sweet spot. Basically, you want enough water to not suck in air but not too much that it overflows to your backup drain pipe. Having a valve on the return pump helps to dial in things as well.

A couple of additional pro tips: Use a gate valve on the main siphon drain and not a ball valve. After making an adjustment to anything or even after turning your return pump back on, give it 10 minutes or so to settle back down. A lot of times when I first turn back on my return pump after feeding or a water change, it will overflow into my back up drain for a few minutes before settling down back into the sweet spot.

 

[Sgt Jonny Cat]

Thank you so much...this makes much more sense!

 

[on the spot]

I'm researching the Herbie drain and I read that the main siphon drain needs to be under at least 6 inches of water...6 inches of water is ALOT to drain when the return pump is shut off. ( I calculate approximately 30 gallons of water going into my sump.) Is this correct? Or am I missing something?

Even if the siphon were 6 inches under water, it would only be six inches under water in your overflow box. One gallon would be a big box.

HTH

 

[nereefpat]

Even if the siphon were 6 inches under water, it would only be six inches under water in your overflow box. One gallon would be a big box.

HTH

There it is.

 

[on the spot]

There it is.

even a broken clock...

 

[homer1475]

Even if I pull all my pipes and empty my overflow, it's only 2 gallons on my 80 with center overflow.

 

[Sgt Jonny Cat]

Even if I pull all my pipes and empty my overflow, it's only 2 gallons on my 80 with center overflow.

I see what you mean, however the overflow weirs in my tank have slots at the bottom and the middle so I'm thinking the water will continue to fill the box until it goes bellow the siphon drain. Am I missing something?

 

[homer1475]

I'm going to assume you have a typical overflow box in a glass tank(glass box with plastic wrapping it), if this is the case, the bottom and middle slits are only in the plastic and do not enter the actual glass overflow box. The slits are only so the water between the plastic and glass does not go stagnant. Water only enter the glass box over the top of the weir teeth.

Water will drain down to your weir teeth, but again it should still only be a couple gallons.

Here's a quick and dirty way to figure it roughly out. Measure from the waterline(top of the weir teeth) to the bottom of your weir teeth this will be your height of the tank, input the results into a volume calc. That will give you how much will drain out of the tank(assuming you have a siphon break), then add in maybe another gallon.

RC Volume Calculator

All in all it should still only be a couple gallons.

 

[Sgt Jonny Cat]

I'm going to assume you have a typical overflow box in a glass tank(glass box with plastic wrapping it), if this is the case, the bottom and middle slits are only in the plastic and do not enter the actual glass overflow box. The slits are only so the water between the plastic and glass does not go stagnant. Water only enter the glass box over the top of the weir teeth.

Water will drain down to your weir teeth, but again it should still only be a couple gallons.

Here's a quick and dirty way to figure it roughly out. Measure from the waterline(top of the weir teeth) to the bottom of your weir teeth this will be your height of the tank, input the results into a volume calc. That will give you how much will drain out of the tank(assuming you have a siphon break), then add in maybe another gallon.

RC Volume Calculator

All in all it should still only be a couple gallons.

You're the BEST! You make perfect sense. I noticed the overflow boxes are just how you explained. Thanks for clearing that up!

 

[homer1475]

Glad I could help!

Your welcome.

Now that that is cleared up, can I pick on your choice of football teams? :lolspin:

 

[Sgt Jonny Cat]

Glad I could help!

Your welcome.

Now that that is cleared up, can I pick on your choice of football teams? :lolspin:

How dare you!!! We love our patriots up here...:inlove:

 

[BrettDS]

Herbie drain question

I'm going to assume you have a typical overflow box in a glass tank(glass box with plastic wrapping it), if this is the case, the bottom and middle slits are only in the plastic and do not enter the actual glass overflow box. The slits are only so the water between the plastic and glass does not go stagnant. Water only enter the glass box over the top of the weir teeth.

Actually this is only partially correct. Water does enter the overflow box through those plastic slits, but they don't go straight through. There is a channel that brings the water up to the top of the overflow box just under and behind the weir teeth. On most built in overflows like that you can pull the plastic front panel up and off and see how it works (and clean behind it)

But as homer said, because the water goes up the channel and over the top the water in the tank won't drain past the top of the overflow box when the return pump is off no matter what the drain height is.

 

[homer1475]

Actually this is only partially correct. Water does enter the overflow box through those plastic slits, but they don't go straight through. There is a channel that brings the water up to the top of the overflow box just under and behind the weir teeth. On most built in overflows like that you can pull the plastic front panel up and off and see how it works (and clean behind it)

But as homer said, because the water goes up the channel and over the top the water in the tank won't drain past the top of the overflow box when the return pump is off no matter what the drain height is.

I know it does actually enter the overflow box, but only when the system is running(need the siphon of the water going through the weir teeth, and over the glass for it to work properly). In this instance it wasn't necessary to explain how it actually worked only that when the system is off it does not drain down, or co ti use to siphon from those slits/holes.

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