Part 3 : Here
Part 4 : Here
Apart from silencing the siphon outlet another improvement that can be made is to increase the aeration obtainable from down spout.
Various ways can be done, I am trying out about 3 method and see which one could produce best aeration with minimum of noise as possible.
The one I already tested are like in my video below using down tube with lots of holes, this effectively reduce noise and at the same time increase aeration.
Another way I yet to try is base on the Aquarium pump aeration, make a fitting on the down spout that replicate this function. I yet to fabricate it and conduct any testing.
It work on an Aquarium pump it should work on a down spout, just that how effective it will be is yet to be seen.
The third method is a bit complicated to explain, I need to make it first before I can display it photo. This too need to be tested.
I have successfully made the siphon outlet for my installation its : Here