To shield or not to shield (UV)

[chris_h]

I currently am using two 250 watt metal halide pendants on a 75 without any uv shield. They used to have shields but they melted. I noticed the light was slightly bluer after I removed the melted shields so I did not replace them. The corals did not seem to mind either.

I want to add an even bluer look to my tank. I am going to take the ballasts from my pendants and build a hood with 4 40 watt NO atinics and the 2 250 watt halides. With the extra UV, should I add a uv shield? Does UV reduce growth rates in the aquarium?

 

[AnotherGoldenTeapot]

Depends on the bulb.

Most screw in type bulbs have built in UV protection.

Most (read this as all) HQI bulbs do not.

 

[chris_h]

I use the screw in type 10K hamiltons. I know UV shields are not required, but I wonder if they would be beneficial.