I wouldn't turn it on unless you have a problem... I have no experience with big tanks like this, but on my 55 I had a UV sterilizer running for probably a week in the last 5 years...
It's not just for algae, it's for pathogens too. This tank is going to have some pricey Apistos, and maybe some Discus or Altums.
In the past, I've never had UVs on a timer. I'm going to have to do some research and calculations on exactly how long to leave it on to protect the tank, and obviously I'd like to leave it on for the minimum time.