My ears is killing me

[Avi]

Okay, the Stockman Standpipes that I fabricated completely silenced both of the hang-on overflow boxes....except....for a noise that sounds like a toilet flushing from one of them (the other doesn't do it at all. I don't know if this has anything to do with it, but the water level in the one that's not making the noise is higher than in the one that does make noise. In the one that doesn't make the noise, the water is at the intake cutouts and in the one that does make noise, it's about 2 1/2 inches down from there. The tank is completely level, by the way). The flushing noise happens about every 20 seconds, and I think that it's happening because air is collecting in the accordion tubing that goes from the overflow down to the sump. I think the air collects and when there's enough, it forces its way down into the sump, causing that noise. I tried a slightly larger hole on the caps of the Stockman Standpipes, but they gurgled consistently when I tried that. Can anyone tell me the fix on this? Thanks

 

[darb2]

Shouldnt both standpipes be the same height?

 

[Avi]

They are...everything is equal in the two Standpipes and the tank is level. There might be some very small difference but they measure exactly the same and for some reason they don't behave the same way. The accordion tubing from the overflows to the sump are of different lengths because one is farther from the sump-intake holes than the other and so their angles are condequently different, and that is the immediate cause of the problem I'd guess, but how to correct the resulting air collection in the one that makes the flushing noise is most likely the solution. But how to deal with that is puzzling.

 

[Gatorfreak]

Backpressure in the piping from overflow to sump does affect the water level in the overflow chamber (and therefore affects noise). Does the noisey overflow have the longer length of pipe? If so, that's probably it as you guessed. The website for making the durso standpipes mentions that you can't have backpressure for it to work correctly. If this is the source of your problem, increasing the diameter of the longer tubing should fix it (in theory).

I've setup my own durso standpipe and have been doing lots of tinkering to get it quiet. It's not easy.

 

[Avi]

Just so you can place this into context, it's the overflow box that's CLOSER to the sump-intake (with the SHORTER tubing) that makes the noise.

 

[Gatorfreak]

Well that kinda blows my theory, I guess. If you do figure it out, please post the solution.