Questions about a sand point; How long do they last? Do those filter socks work from sand entering the screens? Are the tablets the only way of washing a sand point? How much water is need to disolve the tablets by means of water going into the well. How far down must a hose go into the well. I have a 1 1/4" sand point down about 25'. How many tablets are needed? Last questions, can one buy these tablets in Canada. Great site, great info. Thank you.