Updated November 9, 2017
You can adjust the critical and warning threshold values for an individual storage pool, which will override SRM global settings, found here in the Global Settings:
Ensure you're at the Storage Home Summary Page:
http://<your_orion_server_name>/Orion/SRM/Summary.aspx
Find the Storage Objects Resource and click to expand and drill into it until you can click on the Pools Detail page.
To verify you're on the right link, move the mouse pointer over the link and look at the URL it shows. For example it will show NetObject=SMSP:xx vs NetObject=SMSA:xx where xx= the unique storage object id in the database.
Find the Storage Pool Details resource and slide the mouse right and click EDIT.
From here you can either plug in your own values and click SUBMIT, or you can click the Use Dynamic Baseline Thresholds, which would then look into the database and pull values we've been polling and then use standard deviation math to suggest a value.
Also see:
Set SRM Thresholds for specific devices