Hue Search facet craps up the date search string sent to Solr

I created a date range facet in Hue Search. It correctly queries Solr, and gets the correct counts per date range. However, when I click on one of the ranges, Solr complains back with this error:

Cannot parse 'start_time:[2014-05-22T00:00:00Z TO 2014-05-22T00:00:00Z 1HOURS]': Encountered \" \"1HOURS \"\"

This is the full error message:

Error while accessing Solr

{"responseHeader":{"status":400,"QTime":3,"params":{"facet":"true","sort":"start_time asc,start_time desc","facet.mincount":"1","facet.limit":"100","facet.date":"start_time","hl.fl":"version,author,cat,category,classification,comments,content,content_type,description,end_time,features,id,inStock,includes,keywords,last_modified,last_updated,links,manu,manu_exact,name,payloads,plugin_group,plugin_name,plugin_version,popularity,price,resourcename,result_id,seen_id,sku,start_time,store,subject,submit_time,text,text_rev,title,tool_version,url,weight","f.start_time.facet.date.gap":"+1HOURS","wt":"json","hl":"true","rows":"15","f.start_time.facet.date.start":"NOW-10DAYS/HOURS","user.name":"hue","start":"0","facet.sort":"count","q":":","doAs":"admin","facet.field":["classification","plugin_name","plugin_group"],"fq":"start_time:[2014-05-22T00:00:00Z TO 2014-05-22T00:00:00Z 1HOURS]","f.start_time.facet.date.end":"NOW-0DAYS"}},"error":

{"msg":"org.apache.solr.search.SyntaxError: Cannot parse 'start_time:[2014-05-22T00:00:00Z TO 2014-05-22T00:00:00Z 1HOURS]': Encountered \" \"1HOURS \"\" at line 1, column 57.\nWas expecting one of:\n \"]\" ...\n \"}

\" ...\n ","code":400}} (error 400)