checkbox filter/search button: can't undo filtering when unchecked

I have a table made with datatables. There is checkbox, which, when clicked filters the table to display only the data I want to see. The problem is that when I uncheck the checkbox, the table becomes buggy. The table.destroy() function does seemingly revert the table back to the way it was, although it looks like it destroys a little too much (rows per page suddenly get ignored + can no longer click on cell, which opens up in another window).

This is what happens: 1. click on checkbox: filters the data correctly 2. uncheck checkbox: table looks as if gone back to normal (but hasn't really) 3. check checkbox again: no longer filters data correctly. (table is now empty) 4. now it doesn't matter if I check or uncheck, the table stays the same(empty)

Here is my code:

var checkbox = $("#checkB");
checkbox.click(function () {
     var table = $('#WTM_LOG').DataTable();
     if (checkbox.is(":checked")) {
            $.fn.dataTable.ext.search.push(
                function (settings, data, dataIndex) {
                    var num = Number(data[4]);
                    if (num > 0) {
                        return true;
                    }
                    return false;
                }
            );
            table.draw();
        }
    else {
            table.destroy();    
        }
    });