Is this UV sterilizer big enough for 300 gallons?

[Miami Reef]

When this tank was being rebuilt someone brought me this sterilizer. A few years later I learned more about parasites and ich and I don't see any wattage or brand information.

No words on the bottom or sides. How do I know if this sterilizatizer is big enough?

 

[vetteguy53081]

Recommended wattage for a 300g us 40-50 watts
In my 660g I run 80 watts

 

[Miami Reef]

Where did you buy yours from? What brand did you use?

 

[Miami Reef]

I checked the bulb...17 watts. Grrrr.