Help with choosing solar DC water pump

Thanks for the suggestion Tom. The idea has crossed my mind, especially when I consider the fact that in former days there was a water mill at the location that I wish to extract from. There is, further down, a small natural weir that I would like to think could be harnessed. However the flow of the river is not great, and indeed the Old "Molino" fell into disuse due to a change of the river flow.

At this time I really need to go for the most practical and maintenance free solution.

Further to earlier posts I have investigated the Grundfos SQ flex pumps but they are not up to the job.

I have had to become "educated" in what the different type of pumps do and do not do.

In conclusion I have found that I need a "positive displacement pump". With a lot of help from a very nice man in UK from Wind and Sun I have been able to put in my application to take the water from the river. We are going to use a Lorentz PS600 HR submersible pump, which, according to the literature, should give me the 900 liters per day using 3 x 24v panels. The wire size I have had different calculations for and they range from  14mm -20mm, but I think this is due to the fact that I am still not quite certain about the overall length of wire run. I am lucky with the solar resource I may be able to get away with a wire run of 280 meters hence the 14mm.( I think!!).

Anyway chaps thanks a lot for the input; it has helped a lot when I was at my wits end!