Help!! One overflow for two sumps?

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Aquarium Advice Apprentice
May 2, 2005
Hello guys. I got a great deal on a nice 90 gal bowfront tank with stand and canopy. The problem is there is a big divider in the stand so my old sump wont fit and im planning on using two smaller sump one on each side. So I was wondering can I use my old overflow box with one 1 1/4 bulhead drain for two small sumps ( one sump use as a wet/dry and to house skimmer the other as a refugium)? Im using 2 mag5 pump for the return line. The overflow box is rated at 800gph so it could handle the flow at 4 1/2 ft but would the water distribute in to each sump and out evenly? Or should I get an overflow box with two drain or should i just get two overflow boxes one for each sump? What do you guys think?

That is exactly what I did...have a look under my tank and see if this helps you out....

I have pics posted in this thread.....let me know what you think!! HTH and good luck

You will probably need to put valves on each side of the drain line so you can adjust the flow from one to the other. I have a dual overflow on my tank 1200gph with 2 drain lines....sorry for the setup my still help you out though....
alrite ill try using two ball valves i hope it works. Any other suggestion of how to make this work?
Is it possible to connect the two sump containers with a piece of pipe? Here is the will never be able to balance the flow perfectly. Even if you get it working just right, your pump flow will change a little as water levels in the sumps change or as a bio film builds up in the lines. Using ball valves sounds like a good idea until a snail, who would otherwise pass on through to the sump, gets hung at the valve and restricts the flow. If you could connect the two sumps with a couple of bulkhead fittings and some 1" pipe, the water level would always equalize in the two and you wouldn't need to try to balance flow anywhere. Anytime you try to balance a pumped system using valves, you're asking for water in the floor. JMHO.
Loganj has a good I had edited my first post here I thought you had a dual overflow. I would definately use a bulkhead and connect the 2 sumps...have the water dump into the sump you have you skimmer in if you have one and then flow into the sump/fuge and then get pumped back into the tank.....HTH good luck...I would be glad to draw someting up for you if you will get me the dementions of the tanks you are using and he cabinet theyhave to fit under....
It might be hard for me to squeeze everything with the balance pipe and the bulkheads. Both my wet/dry and sump is 18" long 16" high 10" deep. So thats about 36" total. And under my stand there is about 22" on both side but the opening on each side is only about 15". Heres a pic so i wont confuse you.


Can you drill holes in the center of the cabinet and plumb through it? That is how I would overcome the problem here. I'm guessing that inside the cabinet the divider is solid and goes from front to back. I would get the sump and the wet/dry positioned on ether side of the divider and drill holes (holesaw 2"+) and run your plumbing through that and plumb the 2 sumps together using bulkheads. Have your water drain into the skimmer portion and then into the fuge and return. I can draw something up on photoshop when I get home.
Thanks for your help ziggy ill look forward to your drawing and by the way i forgot to mention the stand is 13" deep
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