Part 1 : Here Part 2 : Here Part 3 : Here Part 5 : Here
I have redo the water inlet as shown below
Its from below,, and using a straight pvc pipe as feed,, the water distribution to the growbed not done yet. Should be almost like the home kit water feed, with minor improvement.
I do away with ball valve for excess water and make a "saddle valve" to control water bleed off from pump to growbed as photo below shown at full open.
Photo below is at smaller opening... I need to make the hole bigger .. at full bypass
Reason for this "saddle valve " is to make it simple and cost saving, as this set is primarily for school project its best to make it cheap and simple.
To make the saddle valve all you need is a piece of PVC pipe about 2 ~ 3 inches and make a slit along its length. Shown below, saddle and a long PVC pipe assume as the water inlet pipe from pump to growbed.
Slit on saddle will make it grip the pipe and stay in position.. next install the saddle to the PVC pipe and make a hole.. across both the saddle and the PVC pipe in one go.. actually if require you can make more than one hole on the saddle valve.. then more water will be bypass thats all.
Walla... saddle valve complete... this type of valve is best to be use internally within fish tank so that any leak will just return to source and not make any serious water problem.
Ok water inlet done,, I decide to do it this way... get a piece of PVC end cap about 50mm / 2 inches.. drilled lots of holes and place it over the water inlet opening making a strainer.
Note : After trial, its not a good thing to do feed from bottom, has change that on later posting.
If you want to make it cheaper a Nescafe jar cap will do.. or any cap that is big enough works great.. just make as many holes as you desire.
Aerator use is a small unit about 3 watt in power with only one outlet,, this aerator will be running 24/7, not worth to wire it up with additional circuit.
Its completed and as from above, siphon on left and water inlet on right done.
View from below the growbed, with water aerated and "saddle valve" done. This saddle valve I need to make its hole bigger, still insufficient bypass to prevent equilibrium flow. This mini siphon is too small and requires very little water for its operation.
Updated video of set