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SMiles

Metal Halide Heat

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SMiles
, 03-30-2010 at 07:39 PM (1646 Views)
I'm looking for advice and opinion on what amount of water temperature rise is acceptable during an 8 hour metal halide lighting period. I have two, 250 watt mh installed in an enclosed canopy on my 70 gallon reef. I'm using two 4.5 inch fans for cooling which do a pretty good job, but I see steady water temperature increase of about 2/10ths of a degree per hour when the MH are lit. I have my temp controller set to maintain water (heater) temp between 77 and 78 degree f. The conroller is set to shut the halide lights off at 78.4 degree. They stay off for an hour and then re-light. It takes about 4.5 to 5 hours for it to shut off the first time, and then about 2 to 3 hours to repeat the cycle. The 1.5 degree variation over the course of the day seems like it should be OK, but I don't know . Is there any rule of thumb or thoughts on this? Are the periods when the halides are off (actinic stay on) detrimental to my critters. Could I get away with a greater temp increase before I shut the halides off? I appreciate any and all comment.

Steve

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Comments

  1. Tumbleweed's Avatar
    You should be ok with a tank temperature increase. I run my tank in the 79-79.5 range and upto 80.5 on hot days with my MH. I don't have my controller turning off my lights until I reach the 82.5 temp mark.
  2. melev's Avatar
    My reef runs from 79F to 81F throughout the year. Summer it is more stable because the a/c keeps the fishroom stable at 75F around the clock, so my tank only goes up 1 degree each day. In the winter, it's a little trickier. Spring and fall are wild cards since I seize those weeks to let fresh air blow through the house and fishroom, so I have to really be aware of what is going on with the tank's temperature.

    My system starts shutting off lights at 83F. It is very rare for this to happen; I think it only occurred once in 2005 when I was installing my new sump and I had the probes out of water. The sensor got hotter under the MH lighting and shut off my lights, which surprised me. My first thought was that a breaker had tripped and it took a couple of minutes for me to figure out that it was my controller's programming.

    Since you keep your tank a little cooler, setting it to 80.5F as your max temperature would be better, as you don't want a 6 degree climb before the lights shut off. 2 or 3 is tolerable by most corals.