jQuery Grid Plugin - jqGrid

I am manually adding filters to my grid like this:

JQ("#mygrid").jqGrid('setGridParam',
    {
        postData:{filters:JSON.stringify({"groupOp":"AND","rules":rulers})},
        search:true
    });
JQ("#mygrid").trigger("reloadGrid");

After I do this, my exported json has invalid syntax.  Here is my export code:

var grid = JQ('#mygrid').jqGridExport({ 'exptype': 'jsonstring' });

How can I manually add filters and keep my export json valid?