help me silence the overflow!

[smokinreefer]

hey guys,

i've been trying to "neaten" up my old 180 that i set up budget ghetto style way back in the day.

so my overflow is pretty noisy and i figured i'd picked all your brains for some guidance as to how to silence this thing once and for all.

i'll attach a picture, so you can see the current overflow plumbing, please excuse the picture quality as it was taken with my phone.

the tank is drilled in the back and an external "durso" is in place.
the water level in the overflow is just above the 90elbow.
the drain runs down, then across to the other side of the sump.
a mag12 is used as the return pump.

thanks!

[lastlight]

So only one hole? What size is it?

[Ron99]

I tried a durso on a single hole overflow and it was noisy as hell. I ended up making a pseudo herbie attachment for it and it is silent now. the only noise is a bit of the noise form the water actually flowing into the overflow box. Here's a picture of what it looked like:

[smokinreefer]

Originally Posted by lastlight

So only one hole? What size is it?

yup, only one hole. i think its 2". i'll double check. (tank is at my parents house)

[Lance]

Is the noise caused by gurgling in the drain pipe or water cascading down into the overflow?

[smokinreefer]

Originally Posted by Lance

Is the noise caused by gurgling in the drain pipe or water cascading down into the overflow?

mostly from the drain pipe.

[smokinreefer]

Originally Posted by Ron99

I tried a durso on a single hole overflow and it was noisy as hell. I ended up making a pseudo herbie attachment for it and it is silent now. the only noise is a bit of the noise form the water actually flowing into the overflow box.

so... i'd need to:
-remove cap from tee
-add 2 90elbows to make the "U"
is this a secondary drain?
does the top of the "U" need to below the tanks water line?
-add an air valve on top
to fine tune drain?
-add gate valve to main drain
is this necessary?

thanks

[smokinreefer]

Originally Posted by smokinreefer

so... i'd need to:
-remove cap from tee
-add 2 90elbows to make the "U"
is this a secondary drain?
does the top of the "U" need to below the tanks water line?
-add an air valve on top
to fine tune drain?
-add gate valve to main drain
is this necessary?

thanks

so, is that right?

[Ron99]

Originally Posted by smokinreefer

so, is that right?

More or less. The secondary line after the U acts as the emergency overflow. If you look at "herbie" overflows you can see how they are set up with 2 holes using a main drain controlled by the valve and a secondary drain You want to keep the bottom of the U part at about the level of the water in the tank so that little to no flow normally goes down that one. 95%+ of the flow will go down the primary line with the valve.

You need the valve to adjust the flow down the drain to math the flow from your return pump so that zero air is being drawn down that line. it is the air being drawn down that gurgles and is noisy. I have actually removed the air valve entirely as it was not really needed. I still have the small hole in the top ala Durso to vent air.