Noisy Gurgling Overflow - SOLVED!!!!

[Ron99]

I am still fiddling with this 75 gallon tank. it has a single overflow in the upper left corner. It's a 1.5 inch bulkhead and I've got an external Durso type of arrangement. The T section is made of 1.5" PVC. I have a short length of 1.25" hose and then it is reduced to 1" hose. I cannot get this to be quiet. It gurgles loudly all the time. I have tried using everything between 1.25" hose to 0.75" hose down to the sump. The 0.75" hose made it fairly quiet if I pretty much maxed out the flow so almost no air was going down the line but then I worry about something further reducing the flow down the line and ending up with the tank overflowing. I have also tried numerous hole configurations and sizes in the cap at the top and also putting airline down to various depths. Nothing works.

I hope somebody has insights into setting up an overflow with only one drain of this type.

Here's a pic:

[dkcrx]

have you tried useing hard line (pvc) to the sump?
I have mine set up that way, and remove the air line from the top of your pvc cap, mine only makes noise when the small hole in the cap starts to plug with salt, acts as a warning to clean it out.

[fkshiu]

Some suggestions:

- as mentioned try using a hard line all the way down to the sump
- using a sanitary T (I know, they're hard to find in PVC) would help
- tap some threads into the hole at the top and screw in a JG ball valve.

I think the final suggestion would have the most effect because a Durso is all about controlling the amount of air that gets mixed with water. With the ball valve you'll be able to do that. I remember back in the day (waay back) when Wendell at OA first showed me how his Dursos worked with ball valves controlling air intake.

[banditpowdercoat]

Your vent hose is to large in Diameter. It's not matching the drain size to the cap hole, but matching the cap hole to the flow requirements. I have 6 0.018" holes in my cap for venting, about 300GPH drain. and it's silent. Try getting a shutoff on the vent, something you can precicely throttle back untill it's silent.

[mark]

Originally Posted by banditpowdercoat

Your vent hose is to large in Diameter. It's not matching the drain size to the cap hole, but matching the cap hole to the flow requirements. I have 6 0.018" holes in my cap for venting, about 300GPH drain. and it's silent. Try getting a shutoff on the vent, something you can precicely throttle back untill it's silent.

found with my 2" Dursos running between 500 and 1000gph, hole size in each is only around 1/8"

[Tom R]

I find that using Spaflex tubing helps muffle the sound. Spaflex tubing is available at most Hot Tub stores if they do installation.

Tom R