/* Return zero if fill height is zero */
if (Scientific::equals([hFL:m], 0)) return 0.0;
/* Return stored volume */
$v1 = [L:m]*([D:m]*[D:m]/4*acos(1-2*[hFL:m]/[D:m])-([D:m]/2-[hFL:m])*sqrt(([D:m]-[hFL:m])*[hFL:m]));
$v2 = M_PI*[DC:m]*[hFL:m]*[hFL:m]*(1/2-[hFL:m]/(3*[D:m]));
return $v1+$v2;