We have been steady working for a month & 1/2 on our filter project.
We used common materials to make it cost efficient while making it as simple as possible.
In our case I'm using a PLC but it is doable to use timers or mechanical switches.
So here we go:
We're starting with 2 thirty gallon drums
The second barrel is used for a wrap around where top and bottom are cut off and is sliced in four equal pieces.
We drilled 7/8" holes spaced 1" apart. The 40 micron screen will go between the 1st barrel and the wrap around.
One of the sections of the first barrel is cut so we can access the inside of the drum.