Balancing a Dual Sump System

[dofdear]

In process of building out a 600 gallon Display Tank (DT). The tank has an overflow into a sump tank beneath the DT and a separately located second sump in another room. Lets call these sumps Primary Sump (PS) and Secondary Sump (SS), respectively.

Let me define "in another room" or separately located. PS and SS are approximately 15 feet apart but the plumbing goes up the wall from PS 8 feet into the ceiling space, travels another 12 feet and then down the wall with about another 3 feet of plumbing to SS. Both PS and SS are at he same floor level within 2 inches.

The rational for SS is that there is not enough space and clearance under the DT for an adequate sump and skimmer.

Within PS are 2 DC pumps, one to return water to the DT after a UV filter. The other pump sends water from PS to SS for primary filtration including skimmer.
Within SS is 1 DC pump to return water to the DT after primary filtration.

The concern/challenge is keeping the water levels between PS and SS balanced. I am looking at recommendations.

My thoughts are as follows;
1) Add a Balancing U-Tube between PS and SS. My concern is whether that method would work considering the distance and more importantly the height of the setup.
2) Add an APEX monitor/controller system to each sump with optical water level sensors. The APEX would then control the respective DC motor speed in PS and SS based water level.
3) Employing both 1 & 2 above

So what is the Forum's thoughts on how to keep PS and SS balanced? Thanks in advance for you time. Dan C

 

[griss]

@BeanAnimal might be able to provide some insight.

 

[kharmaguru]

If the source water for SS is provided by a pump from PS, and then SS gets returned to the tank with another pump it will be an endless balancing act.

I would make PS a single remote sump (increased in size if necessary) fed by gravity and call it a day. Use the space under the tank for storage or a closed loop with your UV.

 

[dofdear]

The foot print under the tank is only 42" x 60". Not really an adequate place for filtration for a 600 gallon tank. The idea of having a remote sump is appealing but I have concerns with the "fed by gravity" concept.
The overflow box on the back of the tank is 5 gallons. To per se gravity feed the plumbing with a rise of some 8' is doubtful, but I could be wrong. I guess the question is how to maintain the siphon over that rise and the total 15' run from the tank to a remote sump? Is that really practical?

Thanks for responding. Dan C

 

[kharmaguru]

a rise of some 8'

The overflow box would need to be higher than this to work as a siphon. If penetrating the wall at a lower level is not possible then maybe not a good idea.

 

[BeanAnimal]

While it is possible to set this up with some sensors, fail-safes and level control logic; it is an accident waiting to happen or at best a maintenance nightmare. In theory a large enough U tube would work, but priming and maintenance are a logistic nightmare.

Why can’t they be connected by gravity at floor level?

 

[dofdear]

While it is possible to set this up with some sensors, fail-safes and level control logic; it is an accident waiting to happen or at best a maintenance nightmare. In theory a large enough U tube would work, but priming and maintenance are a logistic nightmare.

Why can’t they be connected by gravity at floor level?

To answer your question, there is a hallway and small closet separating the Display Tank (DT) Primary Sump (PS) and the Secondary Sump (SS) located in the garage.
Both the PS and SS will be at the same level if I place the SP on a 6" platform. I think the best solution may be to saw cut approximately 1.5" x 1.5" trench into the concrete floor and place a 1" Sch80 PVC pipe between PS & SS to act as a balance tube. While a lot of work it should be a bullet proof, fail-safe solution.
Question - If I go with the underfloor balance tube solution, does the fact that the SS is 50% larger than the PS impact tube placement? In other words, The balance tube will exit the PS and drop down say 4" into the trench and run to the SS where it will then climb up an equal distance and enter the SS. Does this make sense?

Thanks to all and please keep the advice coming. Dan C

 

[BeanAnimal]

You still have the problem of gravity feeding a sump and a pump taking water from that sump and not returning it to where gravity completes the loop. The only way this works is if gravity feeds the PS and water freely flows to the SS and is then returned to the DS with a return pump. You can’t pump water to the SS.

So the trench likely needs to be one or more 2” pipes, depending on flow rate and relative head heights.

You will also need a way to clean them out ( a wye and plug at each end maybe).

 

[dofdear]

You still have the problem of gravity feeding a sump and a pump taking water from that sump and not returning it to where gravity completes the loop. The only way this works is if gravity feeds the PS and water freely flows to the SS and is then returned to the DS with a return pump. You can’t pump water to the SS.

So the trench likely needs to be one or more 2” pipes, depending on flow rate and relative head heights.

You will also need a way to clean them out ( a wye and plug at each end maybe).

Okay, not trying to be argumentative but trying to understand. The PS is gravity fed from the overflow of the DT. There would be 2 pumps in PS, one to return through the UV sterilizer and the other to feed the SS. In the SS is a return pump back to the DT. Theoretically, if the output of the PS pump that pushes water to the SS is close to the return pump output from the SS to the DT then the 2 sumps should stay in balance provided the difference does not exceed the ability of the balance tube to transfer/flow water between the sumps. Why would this not work? Thanks, Dan C

 

[BeanAnimal]

In theory the 1” tube would allow water to flow in either direction in attempt to balance the head heights in both sumps. In reality, you are likely to end up with a “hunting” oscillation where there is not stable head height in either sump. So neither pump will have a steady head and flow will fluctuate, as will the overflow, etc.

The larger the common pipe, the less of a chance of steady state instability, but at some point why not just skip the PS to SS pump and complication? Likewise, why place the UV in the PS and instead put it on a closed loop?

 

[dofdear]

I hear ya. Making the UV on a closed loop in the PS is not a problem. I guess my disconnect is how to get the water out the overflow and into the SS where it needs to climb a 8' wall. The overflow box has three 1.5" pipes. If one is used for the closed UV loop and the other 2 would go into a manifold and reduce to a single 1.5" pipe in the wall. The drop from the bottom for the overflow is 3' and then into the wall, up 8' and through the ceiling and down to the SS. The ability to maintain the siphon seems risky at best.
Trenching into the foundation for both a 1" balance tube and another for a 1.5" output from the overflow to the SS is pushing what would be acceptable in terms of foundation modification. Even in separate trenches the 1.5" pipe requires 2.125 x 2.125" Thoughts??? And thanks, Dan C

 

[BeanAnimal]

Where do you live? Is this on-slab or basement with footer?

If trenching were actually an option, then the size of the trench is not really relevant, 2 parallel saw cuts in the slab are two saw cuts, 3" apart or 6" apart.

If you were to cut the slab, then two 2" pipes or a single 3" pipe would carry the flow from PS to SS via simple displacement and the SS would return water to the display up the wall and through the ceiling or back through a second or third 1.5" or suitable pipe in the trench. Mike Paletta has two adjacent tanks with plumbing running across the floor. You can reference that for a similar concept.

That said, this whole thing (one way or the other) is going to be big and messy. That is a lot of pipe and a LOT of air during startups and power downs. Splashing, gurgling, noise, etc.

There is no rule or law about "sump size". A local friend has ~500 gallons and his sump may hold 20 gallons of water while running and 50 while the pumps are off. The skimmer is external and returns to the sump, as are things like the ATSs.

My earnest advice would be to keep this as simple as possible with a single sump or change your layout or floor plan to accomodate a larger area for adjacent sump.

 

[dofdear]

Where do you live? Is this on-slab or basement with footer?

If trenching were actually an option, then the size of the trench is not really relevant, 2 parallel saw cuts in the slab are two saw cuts, 3" apart or 6" apart.

If you were to cut the slab, then two 2" pipes or a single 3" pipe would carry the flow from PS to SS via simple displacement and the SS would return water to the display up the wall and through the ceiling or back through a second or third 1.5" or suitable pipe in the trench. Mike Paletta has two adjacent tanks with plumbing running across the floor. You can reference that for a similar concept.

That said, this whole thing (one way or the other) is going to be big and messy. That is a lot of pipe and a LOT of air during startups and power downs. Splashing, gurgling, noise, etc.

There is no rule or law about "sump size". A local friend has ~500 gallons and his sump may hold 20 gallons of water while running and 50 while the pumps are off. The skimmer is external and returns to the sump, as are things like the ATSs.

My earnest advice would be to keep this as simple as possible with a single sump or change your layout or floor plan to accomodate a larger area for adjacent sump.

In the southwest. It's slab with tile floor. The foundation is post tension type so there is a limit on the depth of any cuts into the slab due to the cables in the foundation. Safely, 2.25" is the deepest. At this point I could choke my builder because the drawings show the plumbing in the foundation but they ignored it. So it is what it is.

I think the best is to; 1) close loop the UV system, and 2) pump out of PS into SS, get the pumps to balance as close as possible and use a balance tube to compensate.

Still open to other ideas. Thanks, Dan C

 

[kharmaguru]

The foot print under the tank is only 42" x 60".

There is no rule or law about "sump size"

I think Bean is suggesting as the simplest route that 42*60*16(?)/231= 175 gallons, is a big enough sump for a 600 gallon display. Even a 12 inch high sump would be 130 gallons in that footprint. You could still have an external skimmer and UV as well.

 

[BeanAnimal]

As mentioned above, I think that any solution for a sump that far away with that many logistical obstacles is a nightmare of one flavor or another and any benefit is overshadowed by the complexity in both design and long term stability and maintenance. There is plenty of room for a reasonably sized sump under the tank. If your dream is a remote fish room with many more hundreds of gallons of water then I suggest some remodeling. 1” pipe in a 15’ trench is going to unforgiving with maintenance and the “hunting” issue is likely to be a real issue with that small of a balancing conduit between the two sumps.

 

[Hong Kong]

As Im making a new marine aquarium system i will use simple 2 U pipes as my sump will be on the left side of the aquarium height in one cabinet and water level will be allways the same in main tank and sump bcs. of U pipe phisics. For safety reason I placed 2 U pipes as overflow have 3 of them Eclipse Eshopp but distance is from overflow ouside to sump connected with U pipes only 15 cm. And I tested this work perfectly when sump input from U pipe is just few cm bellow the most low level of overflow tank even when pumps is stopped no power black out ect. Yes U pipes no matter distance with proper diameter will work well but remember one thing - whenever you place horisontal any pipe captured air inside will create delay in flow and its allways advisable to place inclination towards output pipes... use 2 same diameter U pipes for double safety.

 

[five.five-six]

If the source water for SS is provided by a pump from PS, and then SS gets returned to the tank with another pump it will be an endless balancing act.

I would make PS a single remote sump (increased in size if necessary) fed by gravity and call it a day. Use the space under the tank for storage or a closed loop with your UV.

I have enough trouble tuning 1 sump, cascading them sounds like a nightmare.

One sump. If you are pumping into a sump and out of one, I would definitely use 2 pumps on each end with redundant water level sensors in the sump. I would use all the same DC controllable pumps and would have a "hot spare" on hand. I would have my sump feed pumps slow down when the sump level got too high and I would slow down my return pumps when the sump level gets too much lower than the ATO trigger level.

The last thing you want is to have all your water pumped out onto the floor.

Don't kid yourself, every pump ails eventually and every tube or pipe clogs eventually.

 

[Hong Kong]

Wrong. Iwaki never fail and still work from 1997, 2 of them perfectly. And Askoll Tronic (now named Fluval SP4)
strong works perfect. I purchased in Hong Kong small shop and used on my first aquarium than when i relocate
from Italy I sell it to owner of marine shop he installed both. Visited him many times last 25 y. pumps is working
and he allways salute me entering shop: Konjichiva Iwaki Arigato.
Existing Iwaki but with American motor as well.
Chinese crap quality pumps even German made in China Tunze fail. My own experience with pumps. Same with car parts
reliability. Someone will say my 2006 Volvo is good. Wrong from era of Ford ahead destroyed.

Buy quality reliable pumps with regular maintenance and cleaning and will work decades. New electronicaly
controlled pumps fail of course everything can happen but why Japanese cars in US is top reliability and not
Bmw GM Volvo Ford as once was?

Too many level sensors can also fail - its your decision we are just suggesting from our experience.
Buy simple Iwaki strong and sleep well. Hundreds of pumps is on market but Iwaki is used where
99,9 % of fluids need 24/365 days to flow without interuption. Iwaki is used in Pharmacy, Chemical processes
endless pumping ect...As members say here have spare one
in loop with existing one on standby when alarm sound open triple valve and simply exchange working one.
All this can be manual or even automatic.

Good decision wishing. Are you sure that 1 sump under will not be enough with live rocks ect? Than build U pipes
and double one for safety. If one pump fail or pipe clodgged another will do work.

 

[Hong Kong]