New tank; sump noise

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Aquarium Advice Activist
Sep 5, 2008
Melbourne Australia
I have just set up my new tank. The is quite a gurgle coming from the sump/weir. Could this be because there is too much water flow?
What kind of overflow do you have? Is the tank drilled or do you have a hang on tank type overflow?
My equipment


I have a 3ft reef octopus biolife. It is a drilled hole in the bottom of the tank leading to the sump. There is a 1/2' pipe at the top it is like an r shape.
Does the drain line empty above or below the water line in the sump? Is it rigid PVC or flex line of some kind? If it is flex line are there any areas of the line that falls below the discharge point in the sump?

I'm guessing this is a 40something gallon tank?? What kind of return pump are you using? What is your overflow rated for? I'm guessing 300gph?

it is a solid PVC pipe. The PVC is under the water. The tank is 100g with a 2100l/hr (550 gallon) return pump. The return pipe is in the shape of a r, the stick of the r has a small hole in and the round part of the r is under the water. If I cover the hole the water in the weir goes down, then surges up and makes a sound like a toilet flushing. Thanks so much for you time!
The hole in the top is to allow the air to escape from the drain line. With the end of the line under the water level in your sump you will get that sound. If you can move the end of the line above the water level, you can put a "T" or an elbow on it to reduce the running water sound.
Gave it a try

I gave it a try; it still sounds like a steam train. There is soooooo many bubbles coming from the weir it could almost act as my skimmer. Any other suggestions?
just looked at how to add photo's

Here are the photo's, hope they explain things a little better. With the the protein skimmer is just added yesterday, I am thinking of mounting it externally as I think it will sit better.

The 1st is my beloved tank (I will be landscaping it this week if I can get the noise down, the rocks are not in place).

2st photo is in the weir the top grey tubing is the water returning to the tank. The pipe under this is the return water that looks like the r there is a 5mm hole in the top.

3rd photo is a close up look.

4th photo is a look at the sump


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Very nice looking system.....but sorry, I can't really help. I'm looking, but can't really decipher what I'm looking at. If you are hearing alot of gurgling, all I can suggest is make the air hole in the "r" bigger.
I guess I looked at your join date, sorry. No I haven't solved it but I was thinking if I drilled my hole at the top of the (r shaped) drain I would have better air release just curious if it will work before I start drilling holes.
I drilled

I did try it. It seemed to make more noise. I than got some advise from reef octopus; they suggested that I cover the hole with silicon, then slowly make the hole bigger. This has seemed to help; there is still a little more noise than I would like but I think this is what I am left with. Interestingly, as I covered the hole the water level decreased until it made a noise like a toilet flushing. As the hole got bigger, the water level increased until the water was 1/2 covering the round part of the r, this is were my tank is the quietist. I would suggest that you play with the hole size with some bluetac or tap (you could even use you finger). I used my finger to try it then I went with the silicon. Hope it helps!
You can use an air valve and adjust the amount of air coming in. Just drill a hole large enough to thread in an air valve with teflon tape and then open all the way and start closing it until the noise stops.
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