Question on setting up DC submersible well pump

[DanaBlPl]

I bought a Nemo DC Submersible pump http://nemosolar.com/dcsubmersiblepumps/id49.html for our remote well. Using their chart for well depths, it looks like I need #8AWG wire, and it looks like one 100w 12v PV panel should be enough. They said I could run the pump directly off the panel if I had a LVD inbetween. Since we have a slow recharge rate for the well, my plan was to just turn the pump on when the sun is shining on the pv panel. We live in Southern Colorado and get excellent sun. My question is what kind of switch would I buy for this purpose?

Thanks for your help.
Dana


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