Light heating water

[Jsusisaliv]

I started out with t5 lighting and it heated the water up plus it is not sufficient for my tank. Then I went with the V2 from Reefbreeders. The light is awesome! But it still heats the water, maybe more. It's the 6" recommend height from the top. Yes I had glass tops on because I really like them and would love to keep them on although I did a test and removed them to see if it helped. It helped a little but not much. I'm working on a full on reef and want to keep the water between 77-78 and no higher than 78. At night it drops to 77 but during the day when the lights at its highest the water gets to almost 80 degrees! So I'm fluctuating 3 degrees! That's unhealthy for my fish and from what I read detrimental to fragile coral which would probably suffer from that. I don't want to have to get a chiller but will if I have to but I want to search all other sources first. I seen the fans on eBay that you can hang on the back. Anyone ever use those before? Any help is appreciated.

 

[Kershaw]

Fans can easily lower 2 degrees but will increase evaporation.

 

[mcarroll]

Consistency is more important than the range you are targeting. I kept my reef at around 83ºF when I was using halides. I just set up my heaters so they didn't come on during the day at all but ran when then lights were out to maintain 82.5ºF. Everythting loved it. Also, daytime tempperatures on some reefs in the wild is 86ºF. At 80ºF you are well under any limit.