The bulb life will go way down if you turn it off and on

Christopher wrote:

is it wise to run the UV sterilizer 24 hours a day? assuming that you only
desire a 99.9% sterilization rate you don't have to run the sterilizer that
much (depending upon gph through the sterilizer and tank size). I've read:

9.2 * (tank size / gph through sterilizer) = hours a day UV sterilizer must
be on to attain 99.9% sterilization rate (assuming uniform mixing). This
said my calculation is at most 7 hours a day, should I just run it for 8
hours a day and save my bulb life and power bill?

Should I run it 24 hours a day to achieve 99.999% sterilization or for 8
hours a day?