The invention relates to irrigation by means of sprinklers for agriculture, lawns, golf courses and other applications. The optimal value is estimated by referring to a table prepared in advance, by searching for the optimal value while executing an array process multiple times using different parameters, or by searching for the optimal value from the results of the previous frames. Because the light emitting diodes within the illumination sources are switched from series to parallel connection at a defined kickover point, the voltage-luminance characteristic changes on opposite sides of the kickover point. First water softener 4 is regenerated by salt water from a salt water chamber 14. A preferred embodiment further includes a well plug affixed to the tool attachment portion, the well plug includes a second flow through core capped with a core plug with a core plug release mechanism, which upon activation provides separation between the second flow through core and the core plug, allowing material to flow through said first and second flow through cores.