Preventative medication in growout

[Midway]

Hi there,

I would like to find out if someone out there uses any "preventative" medication(s) in their grow out systems? I'm asking this cause I had a crash in my grow out system 3 to 4 months ago and I lost all my fish to whatever that was. A strong UV is sufficient or would you recommend dosing the system with something good?

Thanks in advice for your advice ladies and gents.

 

[Reefing Madness]