Adding a HOB overflow? How risky is it?

[hbubley]

Hey all,

I'd like to add a sump to my 75g, however I want to do it without drilling into the tank.

This is the overflow box I was looking into:
PF-1000 HOB Overflow

Is this possible without risking a flood? Am I better off just RIP cleaning this tank and drilling it? I have no idea how to go about drilling into a tank, I know I can watch a youtube video but it's really intimidating, and I would have to keep all my fish and corals in buckets while doing this, so I thought a HOB would be my best option

 

[Spare time]

As long as you make sure its clean, I don't think the risk is huge. Most floods I have heard from come from one's that can't self start when power goes off and on (the one's that require a pump for the siphon). I think you are fine.

 

[Zos4me]

When i had my last tank I opted to drill .Loose the siphon and maybe overfill tank

 

[MoshJosh]

I asked awhile back if anyone had ever seen one fail, and I didn't really get any responses. I think as long as you are keeping it clean and periodically making sure you aren't building up air in the siphon you are probably good

 

[mnl119]

I asked awhile back if anyone had ever seen one fail, and I didn't really get any responses. I think as long as you are keeping it clean and periodically making sure you aren't building up air in the siphon you are probably good

I had problems with an overflow that had two u-tube/siphon tubes. Air would collect in one side or the other and break the siphon depending on how they were positioned inside the tank. It was difficult to balance flow in each tube so that this would not happen.

 

[MoshJosh]

I had problems with an overflow that had two u-tube/siphone tubes. Air would collect in one side or the other and break the siphon depending on how they were positioned inside the tank. It was difficult to balance flow in each tube so that this would not happen.

I think I read your thread about that, was it a flow mismatch in the end?

 

[Coffee Soundboard]

I had a Lifereef hang on back overflow back in the day that kept it’s siphon in the event of power loss. It would start back up the moment power kicked back on. It was pretty nice. If I had to do it over though, I’d drill instead.

 

[hoffmeyerz]

I use a Lifereef overflow box on my 75gal and it works great. It NEVER loses siphon, if there is a power break or I stop the return pump for maintenance it equalizes and the u-tube stays full. When the pump comes back on it immediately starts back up.
I will say though that it's the only one I've ever used so I can't compare it to other brands/designs.

 

[afrokobe]

a third experience on life reef. I have been running a life reef overflow for about year. Never lost siphon and clean out the u tubes every couple of months. I still worry about it from time to time lol, so I opted to drill on my new build

 

[mjw011689]

Had one for 5 years on a 40 breeder. Mine did not use a pump and never failed. When I turned my return pump off, it would stop flowing once the water level dropped below the weir. When I kicked the pump back on, it would start flowing again on its own. Never had to restart the siphon.

 

[afrokobe]

definitely recommend life reef or eshopps style. I would not get one with a lifter pump as that can fail i.e. CPR aquatics.

edit: make sure you drill a hole into your return just below the water line, so the syphon breaks when return is turned off

 

[mnl119]

I think I read your thread about that, was it a flow mismatch in the end?

I think I didn't have enough return pump flow to have sufficient velocity through two u-tubes to keep air from collecting. It worked fine with one tube, but the level in the tank was too high. I eventually found an arrangement that worked. Worst case was that one one tube "failed" by filling with air and the other took over. I've since gone to internal overflow boxes.

 

[Goaway]

Ran an overflow box for 8 years maybe 10. Keep it clean, get one that no o e complains about, if you go that route.
This is what i used on my old setup. Cleaned monthly.


Just know the risks. Because, they can flood if not maintained correctly. And some have poor design. Btw dont get the one above if they still sell it. I had to modify mine so suction would break.

Wait a minute.. They all have complaints of some kind.

 

[Badboyan93l]

I've been running an Eshoppe HOB for 6 years never broke a siphon even when the HOB tube had air in it and was sucking small amounts of water...

 

[TokenReefer]

I've been running an Eshoppe HOB for 6 years never broke a siphon even when the HOB tube had air in it and was sucking small amounts of water...

Been running eshopps for about a year. I've not had any issues yet. Implement something to stop the return pump if water in that chamber gets too low and you never really have to worry..

 

[NE reefer]

I’d recommend selecting a HOB overflow box that is set up to have Venturi powerhead attachment. The “U tube” overflow boxes work well and they preform well with respect to power outages. However from my experience the biggest issue is that you eventually will get algae buildup in the U-tubing and this buildup does an excellent job of trapping bubbles and this will lead to siphon breaking. Good luck

 

[PotatoPig]

Adding a shoutout to Jeff at Lifereef also.

Comments:

1. The dual siphon is probably oversized. The biggest risk of a siphon break is too slow flow through a tube. Two siphons = half flow rate per tube for any given total flow. A single siphon version should be enough for a 75 gallon tank.

2. If you get the Lifereef version it’ll come with instructions to soft plumb with flexible PVC. Do. It’s cheap, fast and easy.

3. Get a DC pump with flow rate control.

4. Mitigate flood risk: Put the pump behind a bulkhead that limits how much water it can pump from the sump. Even if the siphon breaks this will prevent a flood as the pump flatly can’t access enough water for an overflow.

5. Mitigate Flood Risk Part 2: Set the water level in the sump so when you turn the pump off and it siphons water from the tank the sump won’t overflow before the return nozzle hits air.

6. Mitigate Flood Risk Part 3: Make sure the return nozzle is not too far below the surface. It will siphon until it breaks into the air. Don’t trust siphon break holes, make sure the nozzle head is set so it can siphon all the way without flooding the sump.

7. Mitigate Flood Risk Part 4. If possible put the sump in a plastic sheet (6mil thick) lined tub constructed using the stand base. This will provide an emergency overflow bath *

note: Parts 2-4 apply to any sump plumbing system, not just HOB.

 

[hbubley]

I can't thank you all enough!! This has been super helpful and I feel confident that I'll be able to set-up a sump! Big milestone :') Hehe. I'll start researching some different overflow box options to choose between, and finalize my gameplan.

 

[JC1977]

Definitely go lifereef if you end choosing a HOB overflow.

 

[ScottJ]

+1 for Jeff at Lifereef. Great product!

I went with the MagDrive 9.5 pump and a ball valve on my 55 gallon. I had to cut the flow a bit. In retrospect, I would go with a DC return pump. The MagDrive is a good pump, but I think a DC would be the best choice.