UV Sterilizer recomendations?

[tmccaffery]

I am looking to get a UV for my Red Sea Max E 170. What wattage should I be looking at?

This one looks interesting. Any good?

https://www.saltwateraquarium.com/adjustable-flow-submersible-uv-filter-sp9uv-9-watt-aquatop/

 

[SantaMonica]

I like a 57W

Temporary UV technique for ich
This technique is simple: Keep a strong UV (such as 57 watts or more) and water pump in storage, and when you encounter ich then put the UV and water pump in a for a few weeks. When ich is gone, remove the UV and store it again. Has worked for me 5 times in a row, if I start using it as soon as any ich is seen.
Ick is always around; it just kicks in when immunity goes down. Good example, I had a powder blue tang forever in a reef pond with no problem; one day he jumped out and after I put him back in he covered in ick. Quick UV solved it in a few days. Nothing else changed.