Templating variable default value

Hi

For data source Elasticsearch we are creating a templating variable Delta with values [ 0,10,20,30,40,50,60,70,80,90,100] and we have an option to select BLANK=ALL or BLANK=NULL as the default value to be selected . We want the default value to be selected as BLANK=60 but it doesnt work and gives me an error For input string: "blank=60" .
Please suggest a workaround

Did you write blank=60? The placeholder text means that if you leave it blank the “auto” behavior is used - that all values are chosen. To use a custom all value, just write 60.