Dont waste your money By Chris on 1/19/2015
Chris wouldn't recommend this product to a friend
I Bought 2 150w heaters and both are not accurate, turned all the way down one heater hit 85 while the other was over 90, I now only use these heaters to do my water changes, still need to unplug to let them cool down though.
it will cook your tank! By vtocean on 1/9/2015
vtocean wouldn't recommend this product to a friend
Bought the 300 watt version and even on the coldest setting stays on with the tank temp over 82 degrees. This has been wildly erratic and is less than 10 months old. Unless this is run on a controller, I wouldn't trust it at all. I had expected a better unit from hydor....needless to say, I use it for water changes only and sometimes need to unplug and wait for the water to cool. Worst part is that at times it seems to work as it should....extremely inaccurate at best and a tank cooker at worst.
Decent heater for the money By Chris on 12/11/2014
Chris wouldn't recommend this product to a friend
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
perry wouldn't recommend this product to a friend
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
AngryBeaver wouldn't recommend this product to a friend
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
Steve wouldn't recommend this product to a friend
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
Tek wouldn't recommend this product to a friend
I have had 2 of these forminternal condensation within the first month.
Good Value For 400W By Jeff on 6/1/2013
Jeff would recommend this product to a friend
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
TROJAN would recommend this product to a friend
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
Anthony wouldn't recommend this product to a friend
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
Kathy would recommend this product to a friend
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
brian would recommend this product to a friend
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.
good heater for the money By Brandon on 8/7/2012
Brandon would recommend this product to a friend
this heater is obviously not the best but it works. I've had it running for about 6 months now and it still works just fine. the numbers on the dial are a little off but once I played with it enough, I got it right where i needed it. Tank runs between 78 and 80. I will probably buy another for a back up and water changes.
No good, like most inexpensive heaters By Dale on 5/23/2012
Dale wouldn't recommend this product to a friend
Got 4 of these in various wattages (100 & 150) to replace some Finnex heaters that stopped working. They are compact but are very erratic, quite often sticking on. (The Finnex heaters stuck off-a little safer I'd say). Would not get again or recommend.
ok By Jason on 2/25/2012
Jason wouldn't recommend this product to a friend
its a good heater for the price but when you live stock is worth so much more go and get a higher grade heater.
Good Heater By JP on 2/8/2012
JP would recommend this product to a friend
I purchased this heater about a year ago, and it has been an all-around good heater for the money. I would recommend this heater to anyone looking for a budget heater that is extremely reliable.
Not my favorite By reeftank85 on 1/2/2012
reeftank85 wouldn't recommend this product to a friend
I tried a couple of these 300 watt heaters, and was not that impressed. The markings on the dial are not off by several degrees. It doesnt stay consistent through the year. I keep my tank around 77 and in the summer the tank will get closer to 80, yet the heater will still kick on periodically. I plan on getting a tank controller soon and not have to worry about it though,
Not reliable By Brent on 12/28/2011
Brent wouldn't recommend this product to a friend
These heaters are not accurately calibrated in my experience, which includes 3 sizes of this model. Turned all the way down (71) they heat the water to about 78 without the lights on.
Great! By Zach on 11/8/2011
Zach would recommend this product to a friend
Looks great! Works great!
Don't waste your time By Weave on 11/4/2011
Weave wouldn't recommend this product to a friend
I bought the 300watt for my 90g reef about a year ago. Noticed my chiller coming on alot even when we had the windows open. Looked at heater and it was on. I tried to turn it back and it just stopped doing anything. always stayed on. Thank god for the chiller or would of had a fish fry for dinner. Works good for short period of time then crapped out. Don't buy.
Hydor Theo Heater - Value for money By Sunny on 8/30/2011
Sunny would recommend this product to a friend
I have the 200Watt heater in my 65 gallon tall aquarium. I have had this heater for around 3 years now and it had been working great. It maintains my tank temperatures really well even in Winter. My aquarium is in the main hall which has alot of windows, being from the north east this room does get very cold in winter, never had any issues with this heater not being able to keep up. It is good value for money and would recommend it to anyone.
Cheap and built that way! By Sarmo on 5/28/2011
Sarmo wouldn't recommend this product to a friend
I had 3 300 watts THEO's. One broke, poisoned and and nearly killed my reef tank. a second one is set at 71 degrees and stays on until 79degrees. i have swithced brands and will NEVER buy another THEO!
Great Heater, it will "shatter" however if impacted. By Loknar28 on 12/6/2010
Loknar28 would recommend this product to a friend
I had a couple of these and they worked great until one of them got to friendly with some live rock in my sump. Although I believe they indicate that it is "shatter resistant" you still need to be careful about placement in your sump as they will break if impacted. They are however laminated so the glass should stay together and not circulate though your system.
Good Economical Heaters By JJ12680 on 10/27/2010
JJ12680 would recommend this product to a friend
I have several Hydor Theo heaters in various wattages (50-400). Although I wouldn't trust my display tank to just one (with a back up I probably would), I can't say enough about their surprising reliability and accuracy. I use these heaters for my make-up water, saltwater for water changes, and freshwater tanks. I turn them on and off, take them in and out, and I've only ever had one break (A 400 watt heater that broke a day after I got it). In my experience these heaters easily maintain a +1/-1 temp variation. If you're looking for an economical, good heater I'd say these are it.