Comments: I have had my share of problems with heaters, sticking on and cooking my fish, glass tube cracking or they stop they working. I've lost count of the heaters I've trashed. I bought one the Hydor ETH300s for my 90 gal discus tank over 4 years ago. It has worked flawlessly holding the temp at 83 degrees even in a cold room. I even removed the 300 watt in-tank backup heater year ago.
<br />I will say this, take your time setting up the hoses. Don't let the weight of the heater hang on the hoses, I use the hook on the heater so it hangs on the back of the tank.

Comments: This is a great heater! It keeps my 30 gallon at a constant 80F with no problems what so ever.

Comments: This is my second Hydor in-line heater, I have a 300 watt on my 75 gal planted tank and a 200 watt on my 29 gal planted tank. I chose them because I wanted less equipment visible in the tank. The thermostat on these is much better than the Hydor Theo heaters. The Theo heaters are great from a shatterproof and auto-shutoff-run-dry perspective, but their thermostats are 10+ degrees off. Not so with the Hydor ETH, they're just right!

Comments: Great idea, works very well.

Comments: Quick and easy to install, nessasary for a Stingray tank, no burns. One thought though, I replaced a 150w in tank w/ this 200w inline and the inline cannot keep up with the heat loss, gona switch to the 300w. Double the wattage to do the same work. I'm heating a 150 ga pond to 78F installed in my basement, ambent temp about 65F.

Comments: This heater was perfect for my application; the only problem I have is that the thermostat is a bit coarse.... if I set it to turn on when the tank is 78 it won't turn off till the tank is around 81 or 82. Luckly, my tank runs at the same temp without a heater almost always so it's not much of an issue. Probably I'll get a temperature controller and run the thing with that.

Comments: I replaced an intank heater for this one. I t perfectly maintains then temp exactly where I set it. Will use Hydor from now on.

Comments: The heater works exceptionally well. I have a pair of Red-eared sliders and had a tough time finding a way to heat the water to 78-80 degrees and keep the turtles from touching the heating element. Heater installed easily inline with the return tube and keeps the water at a balmy 79.5 degrees perfectly. Highly reccomend!!

Comments: Perfect heater except for the on and off click when the heater activates and deactivates. Holds proper temp and nothing looks better than a heater you can't see.

Comments: The Hydor ETH 300 works great, easy installation and best of all I don't see it in my tank. I love it!
<br />PB

Comments: Just bought my second one of these for a freshwater planted, the other is on a reef tank. Keeps temperatures stable, gets the heater hardware out of the tank and doesn't restrict flow. It does what it's supposed to. Nice when products do that.

Comments: Very stable temp, the only problem I had was that it leaked a little from both ends at first try. I had to use teflon tape on both ports and that fixed the problem. My filter is the Fluval 405. I really like the fact that there is no worry about my large fish breaking an internal heater and the tank looks a lot nicer without the internal heater.

Comments: Excellent product, well worth the price because it just works. This is our second unit which, like the first, we use with a 125-gallon fresh water tank serviced by Hagen Fluval 304 canister filters. Two big advantages: (1) no unsightly heater(s) in the tank and (2) superb temperature control with just one unit per tank.