Plumbing two tanks into one sump: ideas?

cody6766

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I'm building a stand to hold my 33g as the main DT and a 20L as a frag/growout tank below it. Finally, my sump will rest on the stand's bottom.

I thought I'd have the 33g overflow to the 20L and the 20 overflow into the sump via a drilled overflow. Is this right? Am I missing something or is it really that easy?
I plan to use powerheads for extra flow, so that's not a concern.

I'm also thinking about buildin in a valve set to bypass the 20 so it could serve as a QT tank if needed.

Any other concrns or ideas?
 
I wouldn't overflow into the tank below. Have both of them overflow into the sump. And the middle tank needs to have a valve on the supply side to restrict flow. A valve is not needed for the top tank, unless you want it as an isolation valve.
 
Cody, is there any chance of flooding the second tank in a power outage the way you are talking about plumbing it?
 
I wouldn't think so, but I've never done it before. I'd think it would fill until it hit the overflow and then drain to the sump....I'm not sure though.

Doug, any input here?
 
I wouldnt see any problem with it as long as the sump can hold the water drained from both of the tanks after the water level in the two top tanks drops to the level of the overflow.
 
I wouldn't think so, but I've never done it before. I'd think it would fill until it hit the overflow and then drain to the sump....I'm not sure though.

Doug, any input here?

Cody,
Just to be safe, I would not drain into the middle tank. Anything ever happens with that drain you would have an overflow. Remember you would all of that water flow pumping into a 20gal tank and that would be alot of water for one drain. If you remember seeing my set up I have a 1 1/2" drain coming from the upper 80gal draining into the sump. Both of my tanks drain into the sump. I would never want that upper tank draining into the middle 100gal. That would raise the level in the middle tank so that I would have to reduce the return water flow into the middle tank. It all has to do with water levels and you would have a hard time trying to calabriate between the two.
Hope this helps. Call me if you need to. Good luck. Looks like a great project.
 
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reading that, I guess I'd need to double up on my return pump capacity then. The flow heading into my 33g alone isn't all that strong. I think it'd be next to nothing when split in half. Something like that will definitely put the two tank system on hold for a while. I'm already stretching my projected budget on the stand build, so adding a return pump would blow it all to hell.
I could easily leave it as a separate system in the same stand and pick up a new return a few months down the road.
 
I can understand wanting to budget to make it right. What pump are you thinking of running with this set up that is too small? I think your idea of having the 2 tanks on the same sump is the way to go. Just a suggestion, I would consider running a separate quarintine tank. And use the pump you are thinking is too small for this split setup for the quarintine tank.
 
You should use the overflow of the higher tank to be the return of the lower tank and then use the overflow of the lower tank to go to the sump. Think of it as one of those decorative fountains the return from the sump is at the highest point and then when the top bowl fills up it drains into the second bowl and then when the second bowl fills up it drains back into the basin where the pump is located. you whould need the same flow rate on both overflows to prevent the smaller tank from getting overpowered by to much flow but if ever there is a power outage you would not have to worry about flooding.
 
that's what I was thinking about doing initially, but Doug mentioned possible flow/balance problems. He's got stacked tanks on a common sump, so I was heeding his warning.

I'm still not quite grasping the full problem with it though.

My thoughts are, if the overflow can flow more than is coming into the tanks, there is no risk of overflow in anything but the sump, and only in the event of a power outage. I have a 20g tank on hand that could replace my 10g sump, so that should provide plenty of buffer down there.

Doug, my return pump is an Ocean Runner 2500. It moves 650gph IIRC. I'm not sure what the head loss is, but I know it doesn't feel like it's flowing a whole lot by the time it makes it the 4.5-5' up to the top of my 33g right now. it moves plenty of water to keep the sump and tank healthy, but I'd be worried about splitting it and running one side up 65" to the 33g and having enough flow. The 20long would only be up about 36" at its rim.

as for the QT tank, I was thinking of adding in a valve set to bypass the 20L, isolating it from the sump, and having the ability to use it as a QT tank when needed. When I get settled for good with the AF I'll look into setting up a true QT tank, but I have to think mobility right now. That's part of the reason for this little project. I also have the biocube that will be empty for the short term that could serve as a quick emergency QT tank.
 
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