push the water through the 300 lb sand/ charcoal swimming pool filter before allowing it into a storage tank at the well. shutting the pump off with a float valve sw. Then use a 2nd pump with a pressure sw to pump the water up to my tower 400 feet away
You can gravity the flow thru the filter and not worry about the extra head, if you use that second "high service" pump; save on capacity and power with the pump down the hole
Might be an ideal application for the "Simple Pump". They offer a solar scotch yoke driver
http://www.simplepump.com/
Turtle
While gravity flow through a 300 lb sand filter with a 30 to 50 lb charcoal secondary filter is an option the the flow rate by gravity through a filter configuration of this size is usually limited to around 3 to 6 gallons per hour. This in itself is not a bad thing it just requires a storage tank above and below the filter also doable. then the water can be pumped up to the tower as needed all this can be set up on an automatic system easily enough.
Simple pumps are really nothing more than modern windmill type pumps with a shorter stroke. Adding a scotch yolk driven by a solar powered gear reduction motor is also a modern version of the old pump jacks we used to power with washing machine motors we could used the electric or the hand pump or when there was wind just allow it to pump that away.
my well is cased with 5" PVC so I can have either or down hole types of pumps a submersible or the simple pump if it were cased with 6" or larger then both could be placed down hole. Or since I have 20 ft of water standing in the bore hole I could place the simple pump slightly above a submersible. These simple pumps are pricey but simple enough that if I wanted I would just machine my own.
The main 2 reasons why I am considering my options is because even after I flush my well I know it will only produce so much clear water the slower the watr is brought out the lower the particulate amount.
I also know that I am going to have to heat the water to a certain point to aid in releasing some of the suspended particulates I will most likely incorporate several filtration and re-circulation methods as well as heat TO heat this would be a perfect use for a small 300 w turbine I have and have been wanting to find some practical use for other than charging a bank. If I decide to use it then I will probably not worry about any kind of controller other than furling. in high winds, just connect it directly to a heating element.