Why don't you add the range filter as another must
term in the bool
filter:
$rangeFilter = new Elastica_Filter_Range();
$rangeFilter->addField('date',
array( 'from' => $datepicker,
'to' => $datepicker1
)
);
$elasticaFilterBool->addMust($rangeFilter);
$elasticaQuery->setFilter($elasticaFilterBool);
You need to use filters, not queries, in a boolean filter. Note I have used Elastica_Filter_Range
instead of the range query you were using.
Also, you know you are using an outdated version of Elastica, the new ones use namespaces!