well i dont know how many folks have even looked at this but the other day i was changeing out a MH bulb from my coralife 492w and decided to take a look at the cooling fan. well i noticed it had a filter media sandwiched between two grills. i took it out to take a look and BAM! a clogged mess!!
i dont even see how it had any airflow at all. its been on the tank about 2 yrs and i bet its never been cleaned.
now this next part.... you will be sceptical about, and i dont blame you because i didnt believe it either. but instead of my daytime high temps reaching 82-84 degrees they only got to 78-80. thats coooool.