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Peace asked in PetsFish · 1 decade ago

How do I keep my fish tank lights from heating up the water?

I just set up a ten gallon fish tank, with heater pre-set to 72. I bought a new 25 watt light that the pet store suggested. Now the water temp. is at 85 degrees. I want to be able to see my fish because the tank is on a book shelf without any natural light. Now I have only been turning the light on when I'm home in the evenings and turn it off before bed,but that still raises the temp. do I just need new lights? Leave the lights off all the time? i want to be able to enjoy and see my fish. What do I do? I have already had a fish die, because I didn't have a thermameter yet.


It's just a fresh water fish tank and I only have a few guppies in it now.

6 Answers

  • 1 decade ago
    Favorite Answer

    Most tank lighting these days are fluorescent tubes, there's no reason at all to use incandescent bulbs which heat up too much and provide the wrong light spectrum anyway. If you don't have any live plants, you don't need any strong lighting and can get by with a 15W or less tube. Use an auto timer switch to control tank lighting for 8-10 hours during daylight hours, you only need longer for plants.

    There are some measures to control heat. If your tank cover has removable flaps separate from the lighting unit, take those off. Too bad if the whole thing is one piece. Don't fill water all the way, so the surface doesn't heat up so much. For a more permanent solution, clip a small fan at the side and angle the fan's flow across the water surface. This increases the evaporation rate which helps to cool water by about 2-4C less than ambient (room) temperature, but you may need to top up water more frequently as the water level drops. You can also use an auto timer to switch the fan on only when the tank lighting is on. Most of such fans are based on the same fans used in PC cases and don't consume much electricity. And you'll really need some form of cooling when hot weather comes in summer.

    For guppies, they do best in temps of 70-77F, so 85 is too high. Even for tropical fish, you shouldn't let the temp get beyond 81F as oxygen deprivation is the biggest problem. Use an airstone & air pump if you notice your fish constantly swimming at the surface gasping for air, also do a water change.

  • 1 decade ago

    Is your light a long skinny tube [fluorescent] or 1 or 2 smaller tubes that you screw into sockets [incandescent]? If it's the last kind you should be able to see a wire filament inside the tube.

    The incandescent lights produce a lot of heat. But if you look in pet stores, and maybe even some lighting store, you can find compact fluorescent bulbs that will work in the same hood, but not produce the same amount of heat. Find 1 that says natural daylight if you get them from a lighting store. And you want bulbs that are long U shapes, not the spirals that you get for lights in your house. They look like this. Try not to get the Coralife 50/50 [it will be too blue, it's for saltwater tanks] or the Colormax [looks too pink].

    If you have WalMart around where you live, there's 1 in their pet department that's about $5.

    If you can't find these, see if you can exchange your incandescent hood for a fluorescent 1. It will probably cost a little more though.

    If what you have is a fluorescent, make sure there's plenty of room above the hood for heat to escape. If it's too close to the bottom of the shelf above the tank, the heat might be getting trapped. Or try propping up the front corners so the heat escapes from the from of the light.

  • 1 decade ago

    From what you are describing your using Incandescent lighting. These have a bad tendency to heat the water up as you have already found out. I would suggest getting a fluorescent light. These are available at all pet stores, good and bad. If your wanting to try your hand at live plants as well there are light set ups for 10 gallon tanks that produce a significant amount of light, if not don't worry about them for now. As a bit of information lights should be on for about 10 hours, but you can adjust that to suit your needs.

    Source(s): 20+ Years of Fishkeeping Experience
  • Anonymous
    1 decade ago

    There's pretty much no way to have the lights not heat the tank, even a lower wattage will still heat it, just not as much. You can switch to 15 watt bulbs instead, the heat rise will be smaller, but it will still rise. Instead, you may have to manually adjust the heater when you want the lights on or off.

    Having their temp up to about 82-84 is ok, 86 isn;t super bad but it's not great. The heat makes less oxygen in the water, making it harder to breath. Either stock lightly or add a bubbler. It also increases their metabolism, so keep them happily fed!

    Best of Luck!

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  • Anonymous
    4 years ago

    i do no longer comprehend if there's a decrease wattage bulb, however the real situation is your hood. It does not vent right. you additionally could have your tank in a foul area. shop it out of direct / pondered image voltaic. shop the lid of the hood open, you are able to attempt drilling extra holes into the hood or working a small fan over the precise to create extra convection, purchase a number of those plastic sticky tabs and be conscious them to the corners of the tank and enable the hood take a seat on those. you will might desire to mess around around with this to locate what's going to artwork terrific. I fairly have had an identical subjects. What I fairly have sugguested labored for me.

  • 1 decade ago

    get a dog

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