Hydor ETH 200 In-Line External Aquarium Heater, 200w, 1/2" hose

If it kept working and was accurate, it would have gotten 5 stars, but it stopped working within a month.Pros: Ok, So this product represents an amazing idea. I love the fact that there is nothing in the tank, the whole tank is evenly heated, and I don't have to reach into the tank to maintain the heater, or change the settings. When I first set up this heater, install was easy, it worked great, heated the tank well, etc. Everything I wanted out of a heater.Cons: The temp dial on my unit doesn't seem to work. I orrigionally heated the tank to 90 degrees (before I put fish in it, on day one of cycling) then I did fine adjustments till it was a the right temp. the knob was at the lowest setting (in the 60-70 degree range) and my temp was still at 80+ degrees. The major problem happened when I cleaned my canister filter. I unplugged everything, cleaned the filter, reassembled and plugged back in, after that the heater would no longer turn on (red light didn't light up, no matter where I put the dial, it hovers around 80 degrees.) My thought is, it has been 90+ degrees air temp in my town for the last few weeks and that is why my temp is still where it should be, because it is around 80 degrees in my house. My worry is that when it cools off, so will my tank.I contacted customer service phone number in the manual to get a warranty replacement or repair, the phone line directed me to contact them via E-mail (I guess they don't do phone customer service???)As instructed by the phone message, I sent an e-mail to their customer service e-mail regarding the issues I've been having... I waited a day or two, and got back this e-mail as a response:"Subject: Hydor USA Customer Service is out of the office.I will be out of the office starting 07/23/2013 and will not return until 07/25/2013.Hydor USA Customer Service is out of the office . We will respond to your email upon our return. Emails will be answered in the order that they are received.Please keep in mind that there maybe some delay in a reply due to the backlog of requests.Have a nice day.Thank you.Hydor USA, Inc.Customer Service"Still waiting to hear about a replacement. I will update this review if and when I hear from customer support.**UPDATE 12/11/13**I never did hear back from customer service, however... Amazon is AMAZING, and ended up helping me out.I found the cause of the problems with my heater to in fact be my tank, and not the heater at all. Shortly after my heater broke I figured out that my tank had a crack in it, and water had leaked out the back/bottom of the tank down the return water tube and into the heater...I have since fixed my tank and gotten a new Hydor In-Line Heater and it has been working like a champ. Due to the issues I had in the past with heating, I decided to pair my heater with a Finnex Max-300 Digital Aquarium Heater Controller. This setup has been working GREAT! My tank temp never fluctuates. I highly recommend this setup to anybody looking to get rid of clutter in their tanks, and who would like a stable, safe, and accurate heating setup.**Update** 2/28/14Still running like a champ. I changed to a 5 stars from a 3 because this heater has been amazing. Combined with the Finnex Max-300 Digital Aquarium Heater Controller, this heater has kept my tank at an absolute steady temp. If your on the fence about this heater, I would say, get it. :)

It is now 2025, I bought this back in Dec 2023. So far no issues and it heats up my tank well.

After reading reviews of this thing overheating, I thought I should share my experience.. Got mine hooked up easy enough and it kept spot on temp for around 3 months. Entered the fish room one morning to find that my tropical tank that should be at 80 F was sitting on 70 F! Dropped 10 degrees in 10 hours overnight. Luckily no fish lost, but had to put the unsightly, space hogging, but tried and true, reliable old heater back inside the tank. I've searched everywhere for info on cleaning this thing out, or to find out if there's some magical fix. I clean my Hydor external filter every 2 weeks religiously and those lines stay extremely clean (pre-filter on intake), so I wouldn't imagine it's gunked up, since they aren't. I'll try to call Hydor tomorrow and see how they stand behind their products that fail, since I buy so many. I have a Hydor Pro 350 external canister filter, several in tank heaters, a few Koralia circulation pumps and a bunch of the bubble makers (which I love, love, love!)I've only had one small problem with any of their products so far. When I got the External filter, one of my screw downs for the intake hose would not go on straight and cut into my hose deeply. I can only imagine it had a burr on the plastic threads that I could not see, or get to (although I tried) in order to fix it myself and get it hooked up and going that day. I did contact the company and sent another out, in no apparent rush, but hey... they sent it, not going to complain. I'm not near as forgiving when it comes to the fail of an electrical part with water involved. It's hard to trust them not to kill all your fish, or God forbid, burn my house down.. with me in it! YIKES! I'll update after I find out their response to the problem.

I bought mine 4 years ago and it still works!! I love that it isn't in the aquarium. It kept the right temp when it was in a suitable sized aquarium. Now it's used in a far too large aquarium with my too small canister filter, lol. It's just extra filtration with my inline UV light. I have another submersible heater as well, but still keep this one going. 2 weeks ago I forgot to plug the submersible heater back in after doing a water change. I'm ashamed to admit it was 2 days before I realized! This heater is for a 50 or 75 gallon aquarium. I have it in 150 gallon. It kept my Oscar from freezing! Sure, it was only 70 degrees in the aquarium. But, we're talking 2 whole days being the only heater in a far too large aquarium with an inside temperature of 60-64 f. (my furnace had quit too!). I love this heater even more now.

Installed on 8 May, 2014. So far so good and hoping for the best. I've read some reviews of the thermostat failing and over heating the water. Almost didn't buy it because of these reviews. however, I really like the idea of not having another item in my small 29 Gal tank, so I went for it. Besides, the same problem can happen with traditional heaters too. So far, I don't think my water has fluctuated even a full degree since installed 48 hrs ago. I will certainly update if any issues arise.Note: it is intended for 5/8" inside diameter tubing so some DIY'ing may be necessary to mate to your system. I definitely did for my Fluval 206. The Fluval must use metric sized hose, because it wouldn't go over the 5/8" barbs and fit loose over 1/2" barbs. I ended up using a hose mender for 1/2" i.d. hose and clamping the heck out of both the Fluval tubing and the 5/8" i.d. vinyl hose I bought to mate this thing up. Had a tough time getting the Fluval tubing tight enough to stop leaking because of the ribbed construction, but got it to work. I look at it every time I pass to check for leaks. So far so good. See pics in the user pic section if interested.