My transaction log for an 18GB database is usually around 2 to 4GB. Last week it blew up to 21GB I think because of a reindexing management plan. I have tried everything I can think of to get this back down to it normal size. I have switched the database to Simple, shrunk the log, and switched back to full. This database might have had a replication on it at some point but I know it shouldn't any more. And I can't find anything under Local Publication or Local Subscriptions referring to this database.
I perform transaction log backups every 30 min. But it still says under the disk usage that all of the transaction log space is being used.
How do I get this transaction log back down to its normal size?