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Heating 80L tank to 20 - 22 degrees C, please assist in heater size and elec usage

PhizinzaPhizinza Member Posts: 2
Hi. I have a tank which after installing the DIY background has come down to about 80L. I want to keep some Endler Guppies and Zebra Danio's in it with my Gold Fish. The tank is in the living room, sits at around 14 - 15 degrees during this Winter, June/July. It is lit with LED lighting so no heat coming from there. Also the polystyrene background protects it from the sun through the window. The room does have a heater on most nights but I am unsure if that actually heats the tank any. I was thinking of getting a 50W heater, but I would like to know how many hours in a day it is likely to be on so I can calculate the cost of running it.

Is anyone able to help?


  • TallTree01TallTree01 Member Posts: 580

    " Heating an aquarium can also be expensive. The larger the tank the more heat is required. Further, a tropical fish environment usually requires a higher water temperature making it more expensive to heat compared to non-tropical fish tanks. For example, a 30 Gallon tank heated at 72 F (22 C) will consume approx. 110 kWh per year. The same tank heated at 82 F (28 C) will consume about 440 kWh per year. That is 4 times as much! "

    30 gallons is around 110 liters and to heat that to 22 degrees it will be about 110 kWh a year.
    So to heat your 80 liter aquarium it will be under 110 kWh per year.
    That ratio is rather nice as 80 liters / 110 liters would mean ( theoretically ) that a 80 liter would use eight elevenths of 110 kWh a year. Which is 80.
    So your aquarium heater would use about 80kwh a year to heat it to 22 degrees.
    I don't know your electricity company but the australian average is 0.38$ per kWh so theoretically your heater would cost about 30.50$ a year to run.
  • MoooMooo Moderator Posts: 7,653
    I would use a 150 watt ;)
    photo mooo_avat.gif "I'm a Doug Addict" photo cow2heartkisses.gif
  • PhizinzaPhizinza Member Posts: 2
    Thank you TallTree, very helpful.

    Moo, all the heaters I have looked at go on a 1 watt per litre system. Wouldn't an 150w be almost twice the sized needed?
  • FraykFrayk Member Posts: 1,009
    edited July 2015
    Yep and perfect for your needs, more is best! Mooo is right. :-bd
  • TallTree01TallTree01 Member Posts: 580
    Assuming it's on a thermostat ( which most are these days ) it won't hurt to go too big.
    But seeing as your only heating to 22 degrees, a 50 watt should be enough.

    Also, upon rereading your post, Ive picked up on a few things. Keeping endler guppies, zebra danios and goldfish in an 80 liter long term will result in many issues:
    1. Temperature differences. Endler guppies are full tropical fish which should be maintained at 24-27 degrees. Goldfish are coldwater which should not be kept above 18-20 degrees long term. Zebra danios can adapt to both but ideally should be kept around the 20 degree mark.
    2. Size issues. Goldfish get big. Really big. Too big for an 80 liter tank. Most goldfish when kept in suitably large aquariums can grow to be over 18-26 cm long. They're also really solid fish and are quite round. They eat a lot and as such crap a lot. They need a really powerful filter and lots of water to keep up with their waste production.
    3. Temperament issues. Goldfish eat small fish when they reach their rather impressive adult size. Fish such as endler guppies. Especially the fry. Zebra danios can usually cohabitate with no issues.

    I urge you to reconsider keeping that selection of fish in an 80 liter for the above reasons. You could invest in a much larger tank ( upwards of 200-300 liters ), get rid of the goldfish ( either by finding them a new home or giving them to a pet shop ) and exchange them for smaller, easier to maintain tropical fish or find an adequately sized pond in which the goldfish can live.

  • TallTree01TallTree01 Member Posts: 580
    If you do continue to keep goldfish in your 80 liter, you should not get danios, endler guppies or a heater. The goldfish will have no problems living in 15 degree water. They are coldwater fish. The other fish will not do well in a small goldfish aquarium longterm.
  • MoooMooo Moderator Posts: 7,653
    The lads are correct, the tank mates chosen are incompatible :/
    Try using the link below, it will confirm our concerns ..
    photo mooo_avat.gif "I'm a Doug Addict" photo cow2heartkisses.gif
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