I have a 55G aquarium that I am setting up for saltwater fish, probably clownfish. It includes a custom built-in overflow to the sump. The water level in the overflow is low. Is this to be expected or should there be a certain level of water in the overflow? If so how can I change this?

image of overflow

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  • 2
    I don't know enough about it, but check out 'The King of DIY' on youtube. He has lots of great info on aquariums, including setting up overflows. I just watched one where he explained about how to set them up to be quieter and the heights to set them at.
    – Dalton
    Aug 17, 2015 at 19:37
  • I think it is supposed to be at least have full. As of right now I just covered the hole with a water bottle cap that has a hole drilled in it to reduce the flow. Until someone has a better idea. Aug 17, 2015 at 20:01

3 Answers 3


My first thought is that your return pump isn't strong enough. The overflow is draining at a faster rate than water is getting pumped back up into the tank. Simple solution is to get a more power pump or to slow down the drainage pipe from the overflow, though that would be more difficult.


Just as I understand you right, you wonder how much water there should be in the left one on the picture?

I would say zero water, it depends on how high your pipe is from the sump. You build it like that so there will be enough big hole so you don´t overfill you aquarium. You will pump water up and it needs to have somewere to go else it will go over your edge and you have water everywere


It looks like you are missing the stand pipe for the drain. A common design out there is the durso standpipe. You can make one yourself from PVC pipe or buy one from their website. There are other designs out there but this one is supposed to be one of the quieter ones(and the one I'm going to try on my new reef tank).

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