Noisy return pipes (bubbling) -- overflow is quiet

[SteveW]

I have a 155G bowfront, with 2 built in overflows. It has 2 All Glass Overflow kits (one for each overflow), which includes a 3/4" return (connected to my Mag1800 pump) and a 1" drain. Sump is a cheap 25G Rubbermaid, unpartitioned. All tubes are connected using a straight barbed insert (no elbows on the drains).

The system is plumbed using PVC hose (not rigid PVC). The drain hoses are 1" braided (reinforced with fabric mesh inside) PVC hose, running freely into the sump.

The overflows themselves are quiet: no gurgling, no flushing sounds, constant water level within.

The problem is in the sump. As a result of air mixing with the drain water, the drain hoses make a ton of bubbling noise: large bubbles come out at the ends. I can see the hoses themselves are not "full" of water - I can see the water level coursing within them as it rushes back to the sump. It sounds like large pot of boiling water. I tried a smaller pump (MagDrive 7) but it had the same problem (although a bit less due to less flow).

I tried submerging the hose ends in the water a bit -- tons of bubbles no matter the depth, and there is too much splashing sound if the hoses are held above the water level.

What can I do to fix this? Would using elbows help? Should I change the hose to rigid PVC (and why would it make a difference)?

Thanks...
- Steve

[trilinearmipmap]

I had the same problem until I read a thread about this on Reef Central.

There are two main approaches.

One is the classic approach. Make a "T" where the pipe enters your sump. Part of the T points upwards, this is where the air escapes. The part of the T points downward, this is where the water goes. Sorry I don't know how to post pics.

The other approach is the one I went with, it is a silent overflow system, a guy named Herbie posted it on Reef Central about two months ago, works a lot better than the T system for me. Do a search for this on Reef Central. What it amounts to is a valve to cut back the flow in your pipe from the standpipe to the sump, and a second emergency overflow drain which is is place just in case the valved line gets blocked up. With the silent overflow system my tank is absolutely silent except for the pump noise.

[SteveW]

Thanks for the reply.

I'm trying the T thing but the T's overflow with water and do a sucking/flushing sound as well.

I'll try this mod if no one else has suggestions.

Thanks again -- it was really helpful!

-= Steve

[robert]

Don’t bother with “T”. “T” will not remove the noise, or the bubbles. It works only as muffler. In order to make an overflow totally silent all the way through, you have to change the free water fall to the siphon. One way of doing this is to attach the gate valve where the water enters your sump to restrict the flow a bit. I alos got rid of durso and replaced it with “U” shaped PVC tube. One end connects to the overflow pipe and other end has a pipe on it with original strainer that goes about half way down inside of the overflow box (see drawing below). What is also important that, the top of the “U” tube is well below the top edge of overflow box teeth, below the bottom edge is even better (my setup). I just adjusted the gate valve to find the sweet spot to keep siphon going without overflowing the tank. Since I am paranoid, I attached my return pump to a simple float switch (via relay) that would turn the pump off in case the overflow gets clogged. This modification might look a bit complicated, but totally eliminated the noise and bubbles in my overflow system.

[MitchM]

Originally Posted by SteveW

....The problem is in the sump. As a result of air mixing with the drain water, the drain hoses make a ton of bubbling noise: large bubbles come out at the ends. I can see the hoses themselves are not "full" of water - I can see the water level coursing within them as it rushes back to the sump. It sounds like large pot of boiling water. ...

Thanks...
- Steve

I had the same problem. I took a couple of plastic bags, cut the ends off and used a nylon tie to secure them to the ends of the hose.
It's a simple baffle system that works great.
Lets water through itself kinda like a windsock at the airport.

Mitch

[Snoop Dog]

I had the exact same problem, I put a ball valve at the end and limited the flow. I then built a small box out of egg crate and placed cotton inside it. The ball valve rests directley onto the cotton and muffles any surpluss sound.

[Fish]

I got rid of my durso and used a ball valve on the drain to restrict the amount of water draining to match the amount that the pump puts out. The overflow and sump are totally silent because no air goes down the drain. I also learned this from Herbie's post on reefcentral and it is by far the best solution I know of.

Here's a photo of the water level staying constant between the overflow and the drain. The other pipe that you can see in the overflow box is just for backup incase the main one got clogged:





The only time I would ever recomend using a standpipe to silence an overflow is if I had one of these online stores that charged outrageous prices for something that's just pvc, or if I kept my sump in the basement where I didn't have to hear it. JMO.

- Chad