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.
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 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.