metal halides & excess heat shutdown

[milo123]

hello everyone, been awhile since i have posted, its our busy time of year and working 7 days wk. i have a question on halide shutdown. just installed 2 175w 14000 MH retrokit with 2 96w actinic PCs on 65gal,(took actinics & ballast out of existing fixture i was using) fabricated hood and installed 4" exhaust fan. everything working fine but i do have one worry, if something should happen to fan, that would be alot of heat build-up. read somewhere (cant remember where) about a thermostat controlled power shut-off, where as if fan should quit, thermocouple in hood would reach its preset temp and shut power down to MH. anyone have or heard of something like this, i know they are available just dont know where to start looking. Thanks in advance.......Dave

[kevinpo]

Hello Dave,
There are several options but before that I would recommend adding an intake fan also. Have one fan blowing in at one end of the canopy and another blowing out at the opposite end. If one fan goes out you will still have some air circulation.
Regarding controllers, it is best to use one with a temperature probe in the water that shuts the lights down one at a time as the water temperature climbs and will turn them back on as the water temperature lowers. Neptune and Reefkeeper both make relatively inexpensive controllers that function as both timers and temperature controllers.

Regards,
Kevin