Hamilton Tech MH Q's

[FranklinP]

This fixture came with 2 5500K 175w bulbs, I would like to change the temperature. I know I cant change wattage without a new ballast but can I get a higher degree bulb? Also the fixture does not have a cover between the lamps and the water. Should it be there? The final resting place of the bulbs will be 1.5 feet above water line hopefully far away from splashing. Thanks.

 

[DougBak]

You can go to a higher K temp bulb with no problem. Just be sure it's the same ANSI rating. Yours will be either ANSI M57 or M137 depending on whether they're pulse or probe start bulbs. Some electronic ballasts will drive both, so check the specs.

Single ended bulbs don't require a glass cover, since the bulbs themselves filter UV radiation. But if you'd feel better about it, you can put a glass shield under the lights. 18 inches should be high enough to not worry about salt spray, but anything's possible.

Doug

 

[squeezix]

18" with a 175 is too long a distance. For maximum efficacy, you want these bulbs more like 8-6" above the water surface. Otherwise you may as well go with high output flourescents.
Getting the bulbs closer to the water will not harm them unless you are super close, like 4-5"