TABLESPACE Query on the GridControl Repository

Does anyone have a good query I could use to to check the status of a Tablespace on an Instance?

The problem we have here is that we're using Nagios as a general monitoring tool for all systems and they do also run sql queries agains our DB's checking for space problems on the Tablespaces with the thresholds for Warning and Critical...  Problem is that the configuration of Nagios is really messy with all the small configuration files laying around on all servers and also the queries they do won't detect the Threshold adjustments I'm doing on some Tablespaces which in the end generates too much error reports from our Helpdesk since they're getting the Alarm most of the times