Part 1 : Here
Part 3 : Here
I spend another few hours doing the outlet making it quieter and I must say the result is encouraging. I decide to use drilled down spout extension approach in silencing my set.
Two reason why I decide on this approach, one aeration I need maximum aeration possible but with less noise and two I need to see whether the siphon is working or not.
Below photo is the modified down pipe, I made it shorter on the initial down tube then an elbow followed by a short piece of PVC then another elbow to point the outlet down and then the silencer/aerator
It works really well in aerating and silencing the outlet it may be possible to make it quieter by employing an outer shroud like Brian Naess's method of enclosing the outlet with a PVC pipe of larger diameter. You can check it at his blog at link Snow Camp Aquaponics.
Below another way to do it if your siphon outlet is of the vertical type. In my installation I am not in favour of vertical outlet because of my growbed height to tank water level is quite close.
Only one growbed left to do, that's the one with outlet that I can't reach from outside the tank.. I need to go in and that not a nice thing to do.
Below the silencer extension tube installed and it only dripping from the leak hole.
BTW holes in this silencer tube its best to make as many as possible, the one shown below is not as many as I would like.
Below, siphon just about to flush over flow has takes place. Water branch out from the aeration holes making it look like a tree root.
Once siphon kick in, the branches disappear or reduce, this may serve as an indication of flush cycle.
Aeration as you can see, is good. This is very important since I have plenty of Tilapia in this tank.
Above one of the inner siphon, its aerating happily. As I said only one left to be done. The noise has reduce considerably. I will make a video comparison once all done.