Sump Baffle Design


New member
Sump Baffles.jpg

I have a few questions for those with experience as this is my first sump design.

1) Baffle A - Most designs I've seen have this baffle at the same height as the first baffle. This creates a waterfall into the return section where the water level will be maintained by tunze lower than the skimmer section and potential bubbles. Should I remove the red section to make it lower than the water line or does it matter?

2) Baffle B - Is it needed to prevent bubbles from the waterfall due to the fuge level being higher?

3) Baffle C - Should the height of this baffle be higher than the back siphon from pumps off to prevent water in sump from entering fuge or does it matter?

Thank you.


New member
Looks good to me, you design is good as is, only thing i did diff was install the bubble trap from the fuge at the bottom so the water dropped in to it and then went back over, this way the bubbles stayed in there, but your way will work as well and really not even needed if your flow is low through the fuge.

baffle c is installed correct.


New member
baffle A is fine at the same height or lower then the first..
baffle B is not required
baffle C is correct as mentioned.

only thing i would change is make your skimmer section larger and your return smaller, or make the fuge bigger if you already have enough room for the ATO will help with any evaporation issues in a small return area...

just do a quick calculation though and make sure you have enough volume left in your sump to account for power off situation in your main tank...dont rely on siphon breaks or check valves to stop the water to the sump...


New member
I have done the calculations. But to confirm your comments I DO NOT want any overflow at power out to enter the fuge?


Team RC
With a center return, there are two ways of supplying the fugue -
1. add a wye off the return pump with a valve to adjust the flow
2. Add a wye off the overflow pipe. This adds a degree of complexity, especially if you're planning on running a Herbie or Bean-style overflow, so option 1 would be easier.

On power out, you can have the water go wherever it wants, as long as it's not on the floor.

One caveat with making the return section smaller, though. THe volume of the return section determines how much time you have before evaporation makes it run dry, fill your tank with bubbles and eventually burn out your return pump. An ATO will mitigate this somewhat, but we've all had times when we don't get to filling the ATO reservoir and it runs dry. I would make sure you've got enough volume in the return chamber for at least a day and a half's worth of evaporation, preferably 2.