Part 1 : Here Part 2 : Here Part 3 : Here Part 4 : Here
Update : Here
Set completed, "saddle valve" bleeder hole enlarged, all gravel/pebble in and trial running it. My main worries is weight, 80 kg of pebbles in the growbed. Those that use lighter material should not worry about this.
I use 32mm to 15 mm reducer with extender PVC pipe to adjust water level suitable for growbed situation. I will lower this water height once plants take root and established.
As mentioned earlier I use water feed inlet from bottom of growbed, there is a slight drawback to this arrangement.
As water fill the growbed, water head increase and back pressure will increase on delivery pipe. This increase of back pressure will cause more water to be bypass by "saddle valve", resulting a slow water filling in towards top of water head at highest stand pipe height.
Photo below show water bypass at max height about 8 inches water level in the growbed. Take note of the water jet from "saddle valve"
Photo below taken at end of flush, water level in growbed at its lowest.
If you compare both above photo, you can clearly see that at maximum height water is diverted more and at lowest height less. You have to take into account this scenario if you want to use water feed from the bottom of growbed.
There is also a plus point to this approach, if you have the water feed from below, you can do away with 4 mm leak hole at base of Siphon stand pipe. This is due to water will back flow through the pump if you decide to periodically switches off the pump or power failure occur.
Having said that, the set been running fine and I am cycling it. I will put mosquito eating fish for a start to ensure safe cycling.
I need to change the stand pipe with the without a leak hole on it base.
This is the first single barrel set I made using recycle 50 gallon drum and its a learning process for me. I have identified few drawback and improvement to be made and my next set should be a product of what learned.
I have replace the siphon with one without leak hole since its not needed due to this growbed is fed from below.
The siphon stand pipe base on left is the old and right is the new without leak hole.
Redo siphon stand pipe below with a 32 ~ 15 mm reducer.
Without leak hole, during operation you will not get the drip flow like normally found on my other siphon.
If you decide to have water inlet from top then its recommended to have the leak hole, this to avoid water clog if you decide to have periodic pump off operation otherwise is not a must have feature.
BTW the actual water level in growbed is directly proportional to the strength of the saddle valve jet.. now this is a good indication of system operation once you familiar with it.
Since I do not have any other mosquito larvae eating fish around these two red Tilapia will do.. they are the pioneer in this set.
I am thinking of putting Discuss in here but they are expensive fish, so have to wait until its totally safe.