Overflow box and sump issue

[jkz2970]

I have a 125-gallon reef tank with an overflow box and a 39-gallon sump. The return pump is a Jecod 15,000. The pump is on 100%. I’ve tried everything, but I can’t get the overflow box to balance correctly. The water flowing into the overflow box is only slightly more than a trickle.

Please see the attached photos. I’m confident there is no air trapped in the U-tubes.

Could the overflow box be undersized, or am I missing something?

 

[fishface NJ]

Photo?

 

[jkz2970]

 

[UncommonSense]

Is this a hang on overflow? Or is it drilled and bulkheaded through the tank wall?

Overflow box design aside, those flexible drain hoses are the first things that catch my eye… drains don’t like going uphill for a number of reasons!

 

[jkz2970]

Is not drilled. It is a hang on overflow box. Should I take those hoses out and replace with PVC

 

[UncommonSense]

Is not drilled. It is a hang on overflow box. Should I take those hoses out and replace with PVC

Ah, does this hang on overflow have a priming pump? — that is, a small self-priming pump constantly sucking out of the highest point in the hang on overflow to suck out any air that gets into it!

It is possible to get all the air out of the U shaped plumbing over the rim of the tank via manual siphon, but it can easily get air trapped in it over time, making it “loose prime”, and stop flowing as much… (this subsequently leads to the ATO dumping excessive amounts of freshwater into the system, and/or display overflowing onto the floor…)

Regarding hoses, can you just get the low spot out of them for troubleshooting purposes so water is constantly draining downhill? — pull them to one side behind the tank to take up the slack, perhaps?

Also, a 15,000LPH (~4,000GPH) pump is definitely overkill for any hang on overflow I know of… most max out at or below roughly 1,000GPH!

 

[Euphylliaphyle]

When you say the return pump is on 100%, I assume this means wide-open and never shuts off? Or do you have a float valve or sensor that shuts down the return to prevent DT overflow?
If the return pump is always on and wide-open, then I don't think the problem is in the drain lines. If there was a drain restriction of any significance, the return pump would fill the display to the point of overflowing either over the tank edge or over the overflow box edge and continue to do so until the return pump emptied the sump -- onto your floor!
I'd be looking at the return pump and lines. Can you measure the gph return at the tank, even roughly? Maybe capture a 5 gal bucket of return water and time it to fill? If that's a trickle, take the pump out and test it's throughput without lines. That should tell you if it is the pump or the return lines.

 

[jkz2970]

The pump is blasting water when not using the overflow box into a bucket. I don’t have a way to measure pressure. I think the Jabaco pump has some type of regulator to keep the flow consistent and not blow all the water of the sump

 

[Euphylliaphyle]

Blasting water out through the return plumbing into the display tank, or just the pump disconnected from all plumbing? You need to confirm if there is a restriction in the return line. Do you have a valve somewhere to regulate return flow? It could be a manual gate or ball valve.

 

[UncommonSense]

The pump is blasting water when not using the overflow box into a bucket. I don’t have a way to measure pressure. I think the Jabaco pump has some type of regulator to keep the flow consistent and not blow all the water of the sump

The only thing it has is speed control, you need to set that manually! (It may also shut itself off when it runs dry, but that protects the pump, not the tank…)

You should address the overflow box priming, then try running this massively oversized pump at it’s minimum flow setting to see if the overflow box can keep up with that!

— the sump’s return pump chamber should never be running anywhere near dry during normal operation, if your pump is just emptying the sump into the display tank, then turning off and siphoning water back into the sump from the display; you have a overflow box priming issue, and you need to locate your return pump’s display tank nozzle(s) closer to the waters surface to serve as a siphon break!

 

[UncommonSense]

The pump is blasting water when not using the overflow box into a bucket. I don’t have a way to measure pressure. I think the Jabaco pump has some type of regulator to keep the flow consistent and not blow all the water of the sump

This is a ~4,000GPH capable DC pump… he just needs to turn it down!

 

[jkz2970]

I turned the pump down and it did not make a difference. I also have a ball valve and turned it all the way open and partially closed neither made a difference.

 

[UncommonSense]

I turned the pump down and it did not make a difference. I also have a ball valve and turned it all the way open and partially closed neither made a difference.

So, your primary issue is the hang on overflow box, and/or drain plumbing…

The return pump is likely flowing a minimum of 750-1,000GPH (observed), even on its lowest power setting… this is a LOT for a hang on overflow already…

The first issue to look into is the drain side of the plumbing; can you take up some slack as mentioned above to get the drain plumbing consistently going downhill?— This will help to get “air locks” (air trapped in the plumbing) out of the troubleshooting equation!

You said you’re confident that there’s no air trapped in the U pipes? What make/model is this overflow?

 

[Euphylliaphyle]

Please clarify: Does the pump run continuously, or does it shut off when the tank hits a certain level? If it shuts off, carefully re-read the long post above by @UncommonSense (Thread post #10)

 

[jkz2970]

You guys were right. Thank you so much. Once I fixed the rubber hose and changed the one way valve it is working great. Thanks again

 

[arcwaveaquatics]

Ah, does this hang on overflow have a priming pump? — that is, a small self-priming pump constantly sucking out of the highest point in the hang on overflow to suck out any air that gets into it!

It is possible to get all the air out of the U shaped plumbing over the rim of the tank via manual siphon, but it can easily get air trapped in it over time, making it “loose prime”, and stop flowing as much… (this subsequently leads to the ATO dumping excessive amounts of freshwater into the system, and/or display overflowing onto the floor…)

Regarding hoses, can you just get the low spot out of them for troubleshooting purposes so water is constantly draining downhill? — pull them to one side behind the tank to take up the slack, perhaps?

Also, a 15,000LPH (~4,000GPH) pump is definitely overkill for any hang on overflow I know of… most max out at or below roughly 1,000GPH!

One thing that had worked for me in the past is getting more water into the hang over box on the aquarium side and that would rush that water through the U pipe, clearing the trapped air.