I don't know how to use my Octo overflow box

[Robbie.]

Hi,
I purchased an Octo Ob-200s overflow box and there are no instructions on how to use it. I don't know how the automatic siphon works after a power outage.
Can someone please help me?
Thanks.

 

[tbrown]

I don't know that specific product but typically the overflow tubes stay in the water on both sides maintaining siphon in a power outage. As long as both ends stay below the weird and below the top of the outlet drain on the outside box.

Not my picture but a simplified explanation:

The picture doesn't look 100% right but basically the water level in both sides is the same when the pump shuts off (they equalize) and both ends of the siphon tube stay underwater.

 

[Robbie.]

I don't know that specific product but typically the overflow tubes stay in the water on both sides maintaining siphon in a power outage. As long as both ends stay below the weird and below the top of the outlet drain on the outside box.

Not my picture but a simplified explanation:

The picture doesn't look 100% right but basically the water level in both sides is the same when the pump shuts off (they equalize) and both ends of the siphon tube stay underwThat was very helpful. Thanks

I don't know that specific product but typically the overflow tubes stay in the water on both sides maintaining siphon in a power outage. As long as both ends stay below the weird and below the top of the outlet drain on the outside box.

Not my picture but a simplified explanation:

The picture doesn't look 100% right but basically the water level in both sides is the same when the pump shuts off (they equalize) and both ends of the siphon tube stay underwater.

Thank you

 

[UncommonSense]

Also unfamiliar with that specific overflow, but @tbrown is correct!

HOB overflows are an utter pain in the butt, consider drilling the tank in the long term for a proper plumbed overflow!

What you may or may not know is that these siphon based overflows typically aren’t reliable (assuming you can even get them working) without a vacuum pump running on them constantly, sucking from the highest point in the siphon.

If you don’t already have one, look up “aqua lifter” pumps… just like the hang on overflows; they aren’t great… but, they are more or less the only game in town to make a siphon overflow (partially) reliable…

 

[John Neuzil]

Dont let people scare you. As long as there is adequate flow overflow boxes are very reliable. I used them for years.

 

[Robbie.]

Also unfamiliar with that specific overflow, but @tbrown is correct!

HOB overflows are an utter pain in the butt, consider drilling the tank in the long term for a proper plumbed overflow!

What you may or may not know is that these siphon based overflows typically aren’t reliable (assuming you can even get them working) without a vacuum pump running on them constantly, sucking from the highest point in the siphon.

If you don’t already have one, look up “aqua lifter” pumps… just like the hang on overflows; they aren’t great… but, they are more or less the only game in town to make a siphon overflow (partially) reliable…

Thank you for the pump recommendation

 

[Robbie.]

Dont let people scare you. As long as there is adequate flow overflow boxes are very reliable. I used them for years.

That's reassuring, thank you

 

[UncommonSense]

Dont let people scare you. As long as there is adequate flow overflow boxes are very reliable. I used them for years.

Me too! And had my (thankfully concrete) floor flooded several dozen times before I rebuilt the tanks!

Issues like:
- Snails/etc clogging the aqua lifter and/or inlet plumbing.
- aqua lifter dying.
- HOB overflow not sitting level on tank rim (air bubble in siphon that aqua lifter can’t get out).
- aqua lifter sucking so much water out of external “air lock” during pump shutdown that it fails to re-prime the siphon when return pump is restarted.
- 1/4” tubing fitting into acrylic top of HOB overflow box becoming loose from box and sucking air.
- hyposalinity from these failures with ATO trying to compensate.

These were specifically in the case of a earlier model CPR brand HOB overflow, but the same principle failure points apply to pretty much every HOB overflow design…

 

[tbrown]

I've run plenty of HOB overflows. They're definitely reliable. Depending on the flow going through it, there's no need for a vacuum pump. On my last one, it had two siphon tubes and 1 would lose prime after a couple of weeks of running. I added a spare dosing head I had and sucked 10 mL of air and water twice a day out and never had a problem after that. With that said, the single remaining siphon tube was working just fine, I just liked having a second as backup.

 

[John Neuzil]

Me too! And had my (thankfully concrete) floor flooded several dozen times before I rebuilt the tanks!

Issues like:
- Snails/etc clogging the aqua lifter and/or inlet plumbing.
- aqua lifter dying.
- HOB overflow not sitting level on tank rim (air bubble in siphon that aqua lifter can’t get out).
- aqua lifter sucking so much water out of external “air lock” during pump shutdown that it fails to re-prime the siphon when return pump is restarted.
- 1/4” tubing fitting into acrylic top of HOB overflow box becoming loose from box and sucking air.
- hyposalinity from these failures with ATO trying to compensate.

These were specifically in the case of a earlier model CPR brand HOB overflow, but the same principle failure points apply to pretty much every HOB overflow design…

User error and lack of maintenance like the examples you listed can really cause trouble but the same can happen on a drilled tank.

 

[UncommonSense]

User error and lack of maintenance like the examples you listed can really cause trouble but the same can happen on a drilled tank.

I agree completely on several of those points of failure… however, some of them remain as inherent design flaws to a HOB! — I’ve yet to have a properly designed drilled overflow lead to a flooded floor, and I give them significantly less maintenance than I ever had to give my HOB overflows!

 

[John Neuzil]

I agree completely on several of those points of failure… however, some of them remain as inherent design flaws to a HOB! — I’ve yet to have a properly designed drilled overflow lead to a flooded floor, and I give them significantly less maintenance than I ever had to give my HOB overflows!

Im sure we have both been doing this long enough to know that anything can fail