diff --git a/manifests/params.pp b/manifests/params.pp
index d74da4d..a1785e7 100644
--- a/manifests/params.pp
+++ b/manifests/params.pp
@@ -40,6 +40,7 @@
 # @param [Boolean] ps_dry_run (true = just log, false = actually delete blocks)
 # @param [String] ps_min_age_hours Minimum block age in hours before pruning
 # @param [String] ps_grace_hours Grace period in hours to be extra safe
+# @param [String] ps_sql_template the SQL template to use for checks. 
 ##############################################################################
 class prometheus_cd::params (
 
@@ -98,6 +99,7 @@ class prometheus_cd::params (
   Boolean $ps_dry_run           = true,
   String $ps_min_age_hours      = '4',
   String $ps_grace_hours        = '1',
+  String $ps_sql_template       = 'Changeme',
 
 ) {
   # defaults
diff --git a/templates/prune.env.erb b/templates/prune.env.erb
index 0edc507..0f99edc 100644
--- a/templates/prune.env.erb
+++ b/templates/prune.env.erb
@@ -17,4 +17,5 @@ MIN_AGE_HOURS=<%= @ps_min_age_hours %>
 GRACE_HOURS=<%= @ps_grace_hours %>
 
 # SQL template to check if block exists in PostgreSQL
-CHECK_SQL_TEMPLATE="SELECT 1 FROM metric_values WHERE metric_time >= to_timestamp({min}/1000.0) AND metric_time <= to_timestamp({max}/1000.0) LIMIT 1;"
+# @param [String] ps_sql_template the SQL template to use for checks.
+<%= @ps_sql_template %>
\ No newline at end of file