Good Value For 400W By Jeff on 6/1/13

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 5/8/13

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 5/5/13

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 3/22/13

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 11/30/12

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 8/7/12

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 5/23/12

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 2/25/12

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 2/8/12

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 1/3/12

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 12/29/11

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 11/8/11

Zach would recommend this product to a friend

Looks great! Works great!

Don't waste your time By Weave on 11/4/11

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 8/30/11

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 5/28/11

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 12/6/10

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 10/28/10

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.