Aquarium sump mismatch

[appacalypse]

Hello, thank you for taking the time to read this.

I recently set up a trigger systems sump for my 75 gallon tank using an overflow box I got off of OfferUp.

I originally had an FX6 running. What I did was I used the overflow box with 1inch pvc draining into the sump and reused the FX6 tubing for the return.

What I'm finding is that there seems to be some kind of aquarium/sump mismatch. I.e. every so often the pump section of the sump runs dry.

Because I bought the overflow off of OfferUp, I don't know what it's rated for in terms of gph. I bought a pump that does around 800gph. Adjusting for head height that probably brings it down to ~700 conservatively.

Is the pump in the sump running dry every so often because of the possible mismatch or evaporation?

I can't imagine losing that much water based solely on evaporation.

Unfortunately, I'm not home so I can't see what's going on myself.

Any suggestions or tips?

This was my first sump setup and I'm still trying to figure out what to do.

Thank you for your time and consideration.

 

[Hemmdog]

Evaporation is surprising. You need to get an ATO to top it off with Rodi for you while you aren’t home. The water level in the return section should stay consistent.

 

[Dragon52]

How often is every so often, hrs/days. You may need a valve on the return side to adjust flow back into the tank or get a bigger overflow. As stated above you may need to add an ATO system if it's days.

 

[appacalypse]

How often is every so often, hrs/days. You may need a valve on the return side to adjust flow back into the tank or get a bigger overflow. As stated above you may need to add an ATO system if it's days.

It's days. I am surprised that evaporation would be the cause.

Does the issue have nothing to do with the overflow/pump possible mismatch?

I really wish I knew what the gph of the overflow box is.

 

[Flippers4pups]

ATO is highly advisable. Yes, evaporation can be substantial depending on humidity levels in the home.

If the overflow bulkheads are undersized for the return pump, the return pump will push too much water into the DT and cause the DT to flood. This will cause the sump water level to run low. Using a gate or ball valve after the return pump should control the water level in the DT. If the return pump is too large, then buying a smaller/proper pump will be needed.

Return lines back into the DT from the sump should be just at water level in the DT, no lower. This will allow during a power failure the back syphon of water into the sump to break syphon soon and not cause a flood in the sump.

 

[Dragon52]

It's days. I am surprised that evaporation would be the cause.

Does the issue have nothing to do with the overflow/pump possible mismatch?

I really wish I knew what the gph of the overflow box is.

You'd be surprised how much water can evaporate, I have a 5gl ATO container that last me 7 days in the summer but 5 days in the winter. I think part of that is the heater works harder in winter time but not sure.

 

[appacalypse]

Filled the sump pump area with RO water. Few hours later, water level went down again..

This is more evidence to suggest pump overflow box mismatch.
My guess is that the pump that I got (rated for 880gph) is pumping the water faster than the overflow box is able to drain (or there is some minor leak)

Ugh..
Any suggestions?

 

[zalick]

Not a pump mismatch.

Assuming the overflow box water level is constant and your tank is not oveflowing to the ground then the rate the pump is pushing the water up equals the rate of water coming down.

You are seeing evaporation. What is your salinity at?

 

[appacalypse]

Not a pump mismatch.

Assuming the overflow box water level is constant and your tank is not oveflowing to the ground then the rate the pump is pushing the water up equals the rate of water coming down.

You are seeing evaporation. What is your salinity at?

How am I seeing evaporation if I just added water and the pump portion of the sump was @ the water level line and then decreased. I can understand if that was the initial thought however after implementing the most recent intervention of adding RO water to the sump area, I do not see how this can still be the issue.

Please bear with me and explain why you still feel that it is an evaporation issue despite me adding water in it.

 

[zalick]

How am I seeing evaporation if I just added water and the pump portion of the sump was @ the water level line and then decreased. I can understand if that was the initial thought however after implementing the most recent intervention of adding RO water to the sump area, I do not see how this can still be the issue.

Please bear with me and explain why you still feel that it is an evaporation issue despite me adding water in it.

Is the water level in you tank staying constant through all of this?

 

[fishguy242]

imo pump too much,put an inline ball valve on return line ,wait on ato if pump is too much ato going to add water and repeat as tank spills on floor

 

[appacalypse]

Yes.

 

[zalick]

The water can only be going one of three places.
1. The DT
2. The overflow box
3. The air via evaporation.

If your DT and overflow box water are staying constant then it must be evaporation.

 

[W1ngz]

This is hard to visualize without photos of the sump and the overflow box but it's entirely possible to pump water up faster than it comes down and flows over/under all the baffles and gets back to the pump. You might have what, a gallon of water in the return section, which can very easily be taken up and be hard to notice in the display level and sump level.

Some pumps have a flow restrictor on the intake of the pump built into the housing. I'd check there first.

 

[zalick]

This is hard to visualize without photos of the sump and the overflow box but it's entirely possible to pump water up faster than it comes down and flows over/under all the baffles and gets back to the pump. You might have what, a gallon of water in the return section, which can very easily be taken up and be hard to notice in the display level and sump level.

Some pumps have a flow restrictor on the intake of the pump built into the housing. I'd check there first.

If it pumps it up faster than it comes down, then it must be accumulating up top right? At the exact rate of the difference between the flows. If that's the case, his tank would be overflowing.

 

[W1ngz]

If it pumps it up faster than it comes down, then it must be accumulating up top right? At the exact rate of the difference between the flows. If that's the case, his tank would be overflowing.

Except down is not only down, it's also got to get over the sump baffles. The preliminary chambers will never drain into the return section unless there is enough water to flow over the baffles. Unless his sump is overfilled, the only water that is of any consequence is the normal volume of the return section of the sump.

If his sump is just a wide open 40 breeder, then sure, even half full, there would end up being 20 or so more gallons pushed into a display that probably only has a margin of 3-4 gallons to get over the rim, but a sump with a walled off return cannot pump up more water than is in the return section.

 

[zalick]

Except down is not only down, it's also got to get over the sump baffles. The preliminary chambers will never drain into the return section unless there is enough water to flow over the baffles. Unless his sump is overfilled, the only water that is of any consequence is the normal volume of the return section of the sump.

If his sump is just a wide open 40 breeder, then sure, even half full, there would end up being 20 or so more gallons pushed into a display that probably only has a margin of 3-4 gallons to get over the rim, but a sump with a walled off return cannot pump up more water than is in the return section.

True. In that scenario, the system would eventually stabilize and it sounds like his is not? I assumed from his posts that it was running what appeared to be normally for some time which would mean all sections of the sump were full. Then not until he got home did he realize the return section was much lower than he thought it should be.

To the @appacalypse - can you please post some pictures? Or let us know if the water levels in the display tank, overflow and first sections of the sump are constant? Is the only water level changing in the return section?

 

[W1ngz]

the system would eventually stabilize

Probably it is stabilizing, with the extra gallon or two from the return stuck in the display waiting for it's turn through the overflow. @appacalypse you could verify this with a piece of tape at the water level when you first start the pump and things seem happy, and then after the return section has drained and the pump starts sucking air you'll probably see the water level about 1/4" higher than it was. In a 75 gallon tank, 1/4" is just about 1 gallon of water.

Whatever you do, don't put an ATO on this tank until you get the water flow sorted out, or you definitely will flood it.

 

[appacalypse]

@zalick @W1ngz
Thank you guys. Yeah. I'll send a picture in the upcoming day or so. Just finishing up exams.

Really appreciate the time and patience.

Some additional info..
It's a trigger systems 26 sump with an 880gph Kedsum pump via Amazon

 

[W1ngz]

No need for pics in that case, the triggers definitely have walled off return sections, and at 6" depth there's about 1.5 gallons in that section. You'll probably see just over 1/4 inch change in the display water level from pump start-up to when your problem manifests.

That pump has an adjustable intake on the front of it. Dial it back. Even after head pressure, 880 is more flow than needed for a 75.