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Hydor Theo Aquarium Heater

  • Decent heater for the money By Chris on 12/11/2014

    I bought this heater for a small nano tank and not really impressed with it. It seems to fluctuate a lot even when the room temp is constant. I will upgrade to a better heater later
  • Horrible heater! By perry on 7/23/2014

    I have had 2 of these heaters break already and have had to call hydor both times and I am still waiting for my other one to arrive. I am planning on buying the Cobalt Aquatics Neo-Therm heater.
  • Broke after 6 months and killed all my fish By AngryBeaver on 2/17/2014

    Heater worked great for 6 months on a 55gal tank... then I started loosing fish.. I did a water change and noticed the temp was very high and the heater was still on.... Using a digital thermometer I found the water to be 86 degrees. Unfortunately, I was to late for most of the fish in the tank... I contacted Hydor for a replacement and they wanted me to send the unit in for them repair it. Sorry not worth my time or effort.. they got my $30 this time, but that will be the last $30 they ever get from me.
  • Would not turn off! By Steve on 1/20/2014

    This heater's gauge seems to have stopped working after only a week! It stays on even when I've dialed it up to the maximum and my water temperature is about 10 degrees below that.
  • Keeps temp stable but prone to leaking. By Tek on 12/13/2013

    I have had 2 of these forminternal condensation within the first month.
  • Good Value For 400W By Jeff on 6/1/2013

    I have the 400W version - it is the cheapest and most powerful among the heaters I use, but it also gives the biggest temperature swing (almost 2 degrees compared to 0.5 for the others).

    My guess is that the temperature sensitivity is not as responsive, so make sure it is fully submerged in a spot with good water flow.

    For this item, I would not recommend buying a model that is rated for a larger aquarium size than what you have.
  • Works as its supposed to By TROJAN on 5/7/2013

    I have a 50w just for my Q.Tank and have not had any issues with this brand and model so thats what im sticking with till it fails to meet the use.
  • Do not purchase! By Anthony on 5/4/2013

    I have had these in the past and they did not perform well. Just recently purchased a 300W unit and after a week, it is sticking on. I like to keep my reef tank warm, but even if I drop the temp towards 70 degrees, the heater kicks on and tries to raise it around 85. I'm running LED's with a Vortech, so not much heat from equipment. House temp is 70 degrees as well.
  • Hit or Miss By Kathy on 3/22/2013

    I love this heater, when it works. I have had one that has lasted over 2 years then cracked when I touched the glass one day. Woops, and another that wont turn off. I use that guy to heat my water for water changes. When it does work, it's accurate, and easy to operate. I haven't given up yet.
  • Not accurate By brian on 11/30/2012

    Temp adjustment is not accurate in the least bit, but what heater is. I've used these for year never had a problem with them but then again I run them on a controller. I would'nt go with this heater unless you use one also.

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