function calcDose(frm) {			
					
	if(frm.poolvol.value <= 0) {
					alert("Please enter a value for your pool volume in cubic metres ...");
					return false;
					}
		              frm.alk10.value = (10 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk20.value = (20 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk30.value = (30 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk40.value = (40 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk50.value = (50 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk60.value = (60 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk70.value = (70 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk80.value = (80 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk90.value = (90 * (frm.poolvol.value * 1.683) /1000);
                              frm.alk100.value = (100 * (frm.poolvol.value * 1.683) /1000);

		              frm.ca_hard10.value = (10 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard20.value = (20 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard30.value = (30 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard40.value = (40 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard50.value = (50 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard60.value = (60 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard70.value = (70 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard80.value = (80 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard90.value = (90 * (frm.poolvol.value * 1.481) /1000);
                              frm.ca_hard100.value = (100 * (frm.poolvol.value * 1.481) /1000);

		              frm.cl_inc_a1.value = (1 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a2.value = (2 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a3.value = (3 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a4.value = (4 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a5.value = (5 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a6.value = (6 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a7.value = (7 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a8.value = (8 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a9.value = (9 * (frm.poolvol.value * 1.539) /1000);
                              frm.cl_inc_a10.value = (10 * (frm.poolvol.value * 1.539) /1000);

		              frm.cl_dec1.value = (1 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec2.value = (2 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec3.value = (3 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec4.value = (4 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec5.value = (5 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec6.value = (6 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec7.value = (7 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec8.value = (8 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec9.value = (9 * (frm.poolvol.value * 7.407) /1000);
                              frm.cl_dec10.value = (10 * (frm.poolvol.value * 7.407) /1000);

		              frm.pc_inc1.value = (1 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc2.value = (2 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc3.value = (3 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc4.value = (4 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc5.value = (5 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc6.value = (6 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc7.value = (7 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc8.value = (8 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc9.value = (9 * (frm.poolvol.value * 7.407) /1000);
                              frm.pc_inc10.value = (10 * (frm.poolvol.value * 7.407) /1000);

		              frm.cl_inc_b1.value = (1 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b2.value = (2 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b3.value = (3 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b4.value = (4 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b5.value = (5 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b6.value = (6 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b7.value = (7 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b8.value = (8 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b9.value = (9 * (frm.poolvol.value * 6.666) /1000);
                              frm.cl_inc_b10.value = (10 * (frm.poolvol.value * 6.666) /1000);

				return true;
				}