I know there's another topic about which pump to buy, but I have a few specific concerns about Well pumps in general.

I have a typical artesian well lined with concrete rings. The water is clear but as its dug through clay I expect some clay or mud particles in the water. I had a small 150w pump which has functioned well but just isn't powerful enough. I need a back up for the village water supply and water for the garden about 4 rai. I changed the pump recently for the biggest I could get locally which was still only 250W. I've had to change the brass wheel/impeler or whatever its called twice in two weeks . The guy who sold it to me says its due to mud and the speed of the impeller. I'm a bit hesitant about buying a bigger pump as I'm concerned about these wheel/impellers which all the well pumps I've seen seem to have. It doesn't seem to be a robust design to me, lots of blades or grooves running at high speed, throw in some mud particles and its an accient waiting to happen. Are there any alternative pump types, diaphram types maybe, or can I get a good pre filter ?

I am not a pump person but maybe if you are trying to draw and push water for a house and 4 rai of land you might need a heavy duty agricultural pump and not a domestic pump. I think the home type pumps are meant for cleaner water and less work.

I'm running water supply to trees in a 4 & 1/2 rai setup. If you are growing trees bushes & plants you will need to set up zone type irrigation or have a mammoth agriculture style pump on off & water everything at once. We have a Mitsubishi 300 watt from the well to the 4& 1/2 rai & the other section of the T runs into the 2000 liter tank & is taken from the tank via a Mitsubishi 200 watt. The 300 is adequate, but is at its peak on the last zone(furthest water outlet) A Grundafos will give you more power than a Mitsubishi or Hitachi style home pump.