Part 1 : Here
Part 2 : Here
Part 4 : Here
Another few hours of fiddling with down spout to get the most out of siphon, finally I arrive at one type best suited for my installation. Others will be differ from my requirement and if you need to make a silencer/aerator one of the design should suit your purpose.
Before that,, let see all type made and tested.. some can be a bit bizarre and some are simple.
This one below as yesterday's post copied from aquarium pump aerator, is a capable aerator., and this photo is its in action.
Next the 50mm adapter shrouded down tube, its a straight 50mm down tube without any inner tube of smaller diameter. It works in aerating the tank.
Then I made the 50mm with venturi pump.
And lets not forget the first silencer, its the simplest and it work but not as silence as those above.
Now the weird and bizarre derivative of above. First the 50mm shroud with inner aeration tube. It work but not significant to put all labour on those extra holes.
Photo below is it in action. You cannot tell much from outside from the basic shrouded.
I did try varying its internal tube length, not much change in it output, so not worth the experimenting.
Then I change the inner tube with this one, having small aerator tube sticking in it.
The small aerator are made from air tube joints, and it work as aerator but not worth the extra work putting in it.
This is it in action, look no differ from the previous.
Things starting to get weirder now, I stick another smaller adapter within the 50 mm adapter, its a 25~32mm adapter.
It flush and still nothing to shout about in comparison to previous.
Another weird one, this time I stick more aerator tubes around the adapter neck, hoping the down flow will give aeration and better mixing when it hit these small tubes.
It so weird it deserve a second take of photo.
Those black aerator piece are made from tube connector that normally obtainable from garden supplies.
It works but again, not worth the extra effort putting into making it. Siphon cut off is a bit slow on this one I have to drill extra holes on the adapter shoulder.
Finally I made this one, a hybrid merging the in-line aerator with a 50mm shrouded silencer. It look like a Bazooka to me.. this hybrid Bazooka is made for a reason.
The reason I made the Bazooka is, testing of all those various aerator/silencer was done with low water. I need to test it again with high water.
On my set, the high water is about 7 inches below the growbed... this is when the overflow occur.
This is the problem with my set, the high water is only 7 inches from growbed and most of the time I have to drain out water in order not to block siphon outlet causing it to be unreliable.
If your high water point is 1 ft or more from growbed then you will not experience any of the problem I had.
All type of siphon outlet fail the high water test except the Bazooka... it work in cutting of the siphon, all other fail in cutting off the siphon.
Photo above you can see the water level is reaching the drain point and the Bazooka work.. the best part is I don't need a double elbow for its installation. Its a straight down tube without any elbow.
Another photo of the Bazooka...
And the winner is in my test......
The BAZOOKA..... :)..
I should not claim victory too soon for this, after about 3 to 4 hours of usage in high water level it too shows sign of unreliable operation.
I drain about 3 inches of water out the tank, so now there's roughly 10 inches of water and I am switching back to double elbow with either 50 mm shroud down spout or the 25mm down tube with holes.
I guess with such high water level and very low clearance between the growbed bottom to water level... I still need to figure out what's work.
Most people will not have this problem, if all else fail I will then need to rise the growbed by a few inches.
One area that I overlooked is as water level in tank increase, so does the water flow into the growbed. This is due to the distance to lift water into growbed is less hence reducing back pressure and increase flow.
This have to be look at to.... so back to the drawing board... so in the mean time I use this for safety... because as long as there are holes expose above water level this one work.
After much thinking this is the siphon situation for my growbed, to make it silent and with aeration. Its a sketch I need to figure out how to make it to within my set limitation, that is 7 inches growbed to max. water height with siphon functioning at that close distance.
Below is another method I need to try, instead of putting the in line aerator vertical, put it horizontal. This arrangement should reduce the overall length of down spout.