Upload data into google via markercluster plug-in with boloons?
===

I upload data on Google Map and using a markercluster. 
The question is how to set boloons to each point? The problem in my case is when I place the bolloons on map, it seems like overriding the same boloon and shows up when clicking in the center of a map. 
The code is: 

       $(function() {
          function initialize() {
             var center = new google.maps.LatLng(55.66, 88.66);
    
             var map = new google.maps.Map(document.getElementById('mapBox'), {
                zoom: 2,
                center: center,
                mapTypeId: google.maps.MapTypeId.ROADMAP
             });
     
             var markers = [];
      
             $.ajax({
                url:'/ajax/map_upload.php',
                type:'GET',
                dataType:'json',
                success:function(data) { 
                   
                   for (var i = 0; i < 1000; i++) {
                      //       var dataPhoto = data.photos[i];
                      
                      var latLng = new google.maps.LatLng(data['coordx'][i],
                      data['coordy'][i]);                 
                      
                      var marker = new google.maps.Marker({
                         position: latLng
                      });
    
                      google.maps.event.addListener(marker, 'click', function() {
                         var infoWindow = new google.maps.InfoWindow();
                         infoHtml = 'bla bla bla';
                         infoWindow.setContent(infoHtml);
                         infoWindow.setPosition(latLng);
                         infoWindow.open(map);                     
                      });
                      
                      markers.push(marker);
                   }
                   var markerCluster = new MarkerClusterer(map, markers);
                   //      alert(data['coordx'][0]);
                }
             });  
          }
          google.maps.event.addDomListener(window, 'load', initialize);
       });   