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Hydor ETH 300 In-Line External Aquarium Heater, 300w, 5/8" hose, Black

3.8 3.8 out of 5 stars 801 ratings

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300 Watt 5/8"

Purchase options and add-ons

Brand Hydor
Special Feature Automatic Shut Off
Color Black
Indoor/Outdoor Usage Indoor
Product Dimensions 3"D x 3"W x 5"H
Power Source
Corded Electric
Heating Method
Convection
Item Weight
1 Pounds
Heat Output
1500 Watts

About this item

  • Suitable for marine and tropical aquariums
  • Easy to use
  • High precision electronic temperature control
  • For external use
  • 5/8 inch hose

Customer ratings by feature

Accuracy
3.2 3.2
Temperature Control
3.2 3.2
Value for money
2.9 2.9

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From the manufacturer

Hydor In-Line External Heater - Original ETH

First and unique external heater for aquariums with the exclusive PTC (Positive Thermal Coefficient) technology. The self-limiting PTC heating element ensures maximum safety against any risk of overheating. The exclusive technology and the high quality of the components ensures a long lasting product. Suitable for canister filters and sump tanks

Product details

  • Is Discontinued By Manufacturer ‏ : ‎ No
  • Product Dimensions ‏ : ‎ 4 x 4 x 12.5 inches; 1 Pounds
  • Manufacturer recommended age ‏ : ‎ 1 month and up
  • Item model number ‏ : ‎ T08203
  • Department ‏ : ‎ Unisex-Adult
  • Date First Available ‏ : ‎ June 15, 2004
  • Manufacturer ‏ : ‎ Hydor USA, Inc.
  • ASIN ‏ : ‎ B0002Z7VQE
  • Country of Origin ‏ : ‎ USA
  • Customer Reviews:
    3.8 3.8 out of 5 stars 801 ratings

Looking for specific info?

Product Description

ETH Heaters are the first external heaters for aquariums with the exclusive PTC technology. The self-limiting PTC heating element guarantees maximum safety against any risk of overheating. Designed to be used on return lines coming from canister filters or sumps.

WARNING:

CHOKING HAZARD -- Small parts. Not for children under 3 yrs.

Important information

Directions

Follow Direction Listed in Manual

Legal Disclaimer

No Returns No Exchanges

To report an issue with this product or seller, click here.

Customer reviews

3.8 out of 5 stars
3.8 out of 5
801 global ratings

Customers say

Customers like the ease of installation using the aquarium heater. They say it's easy to set up and use, and it has a nice clean look. Customers also appreciate the appearance of the product, saying it looks just like the image advertised. However, some customers dislike noise, and disagree on quality, accuracy, leaking, performance, and size.

AI-generated from the text of customer reviews

35 customers mention27 positive8 negative

Customers find the installation of the pet supplies to be easy. They mention that it works great, is easy to use and set up, and that it reaches the desired temperature level easily.

"...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...." Read more

"...It was pretty easy to install and I’m no longer concerned about the turtles breaking the tank glass or heater. It works great...." Read more

"...line that returns filtered water back into your tank, it is a very simple process...." Read more

"...The new one was a little more difficult to hook up in the fittings didn't close as well as the old one. Had to use sealant to keep from leaking...." Read more

20 customers mention14 positive6 negative

Customers like the appearance of the pet supplies. They say it has a nice clean look, and is very nice. Customers also say that it removes the eyesore of having a heater in the tank, and it frees them up decorating their tank.

"...Makes for a cleaner looking setup." Read more

"...It's amazing how much it freed me up decorating my tank, not having to work around and consider space around the heater...." Read more

"...Both units showed evidence of prior misuse...." Read more

"...Like not event by a tenth. Amazingly accurate and removes the eyesore of having a heater in the tank. Well worth the money...." Read more

187 customers mention118 positive69 negative

Customers are mixed about the accuracy of the pet supplies. Some mention that it keeps the temperature pretty consistent for weeks, while others say that the replacement unit has stopped maintaining consistent temperature after 2 months in use. The temperature settings are not as accurate as the old unit, and the temperature in the tank will vary as you get further away from the unit. The unit itself does get somewhat warm.

"...clutter in their tanks, and who would like a stable, safe, and accurate heating setup.**Update** 2/28/14Still running like a champ...." Read more

"...to your desired water temperature and it switches on automatically to maintain the temperature setting...." Read more

"...June 3rd, 2013: DEADnoticed the water temp was lower than usual. looked at heater, no red light for heating...." Read more

"Been using this heater 4+ years from purchase. Easily the best heater for lifetime sakes...." Read more

148 customers mention97 positive51 negative

Customers are mixed about the performance of the pet supplies. Some mention that it worked well, while others say that it stopped working.

"...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...." Read more

"...It works great. Set it to your desired water temperature and it switches on automatically to maintain the temperature setting...." Read more

"...not a chance. plugged it back in, no life. dead dead dead, useless dead.now to see if the manufacturer will play ball." Read more

"...Update: 2/24/2020: it's been over a year now, It's preforming flawlessly, love it!" Read more

69 customers mention26 positive43 negative

Customers have mixed opinions about the quality of the pet supplies. Some mention that it is reliable and well-constructed, while others say that it failed in about 10 months and broke within a few months of having it.

"...not a chance. plugged it back in, no life. dead dead dead, useless dead.now to see if the manufacturer will play ball." Read more

"...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,..." Read more

"...They did, however, use some cheap wire on the inside and some poor components. I sent it back and got another hoping it was a fluke...." Read more

"...All fish have perished. Past my return window." Read more

34 customers mention16 positive18 negative

Customers are mixed about the size of the pet supplies. Some mention that the inside was the perfect size to fit a PVC fitting, while others say that it is rather large and the heater is pretty massive. However, some customers also say that the aquarium is spacious and the multiple mini heaters give the fish more room.

"...So I got this heater . . . it was a snap to install and it perfectly fit my 5/8" ID tubing...." Read more

"...Since it's also pretty fat (much thicker than the hoses themselves), the tank now sits a few inches from the wall instead of almost right up against..." Read more

"...It fit perfectly with my Fluval 207 canister filter because I also purchased two additional Fluval A20016 rubber hose adapters..." Read more

"...Luckily no fish lost, but had to put the unsightly, space hogging, but tried and true, reliable old heater back inside the tank...." Read more

31 customers mention16 positive15 negative

Customers are mixed about the leaking of the pet supplies. Some mention that it works nice, doesn't leak, and keeps their 20 gallon at a constant temp, while others say that it started to leak after about 4 months, and the tank had a crack in it.

"...overall, i'll take it. i'm satisfied now that it's connected and not leaking. i was irritated while i installed...." Read more

"...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..." Read more

"...NO leaks, easy peasy!..." Read more

"...Otherwise, it leaks." Read more

19 customers mention4 positive15 negative

Customers are dissatisfied with the noise produced by the pet supplies. Some mention that it makes a clicking noise when it turns on, and some customers report that the heater starts clicking on and off very quickly.

"...The heater does click when it turns on, even literally at the foot of my bed its not loud enough to be disturbing once you know what the noise..." Read more

"...But tonight the wife heard this strange clicking sound. It was the heater clicking on and off very quickly. The tank as at 75f...." Read more

"...It does make a click noise when the heater turns on and off, but I'm pretty sure most do...." Read more

"...It's not ridiculously loud, but it is something I can hear from across the room, and for a while I thought something was wrong with my aquarium..." Read more

Works well with my Fluval 207, but requires some minor adaptations
5 Stars
Works well with my Fluval 207, but requires some minor adaptations
I wanted to get the heater out of my tank, so I purchased this heater hoping I could get it to work with my Fluval 207. First you need to purchase the Fluval A20016 adapters. However, even with the adapters I found I would get a slight amount of leakage if any pressure whatsoever was put on the hoses. I then applied copious amounts of Teflon tape to the corrugated Fluval hose, particularly on the depressed portions of the hose to "smooth" it out. This worked perfectly and there was no more leaking and the connections felt much more secure. So far the heater has worked well as advertised. However, I am using a aquarium thermostat controller, not the onboard thermostat from the heater.
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Top reviews from the United States

Reviewed in the United States on July 24, 2013
Size: 300 Watt 5/8"Verified Purchase
14 people found this helpful
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Reviewed in the United States on April 6, 2013
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Reviewed in the United States on March 3, 2024
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Reviewed in the United States on June 7, 2022
Size: 200 Watt 5/8"Verified Purchase

Top reviews from other countries

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Andrew Fredericks
5.0 out of 5 stars Accurate, heats quickly.
Reviewed in Canada on May 11, 2020
Size: 300 Watt 5/8"Verified Purchase
Kieran
5.0 out of 5 stars Works great.
Reviewed in the United Kingdom on December 29, 2020
Size: 200 Watt 1/2"Verified Purchase
Edgar Castillo Medina
5.0 out of 5 stars Muy bueno
Reviewed in Mexico on June 20, 2018
Size: 300 Watt 5/8"Verified Purchase
One person found this helpful
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Amazon カスタマー
5.0 out of 5 stars 安定水温
Reviewed in Japan on August 11, 2022
Size: 200 Watt 1/2"Verified Purchase
2 people found this helpful
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Frank Portelli
5.0 out of 5 stars Works
Reviewed in Australia on July 2, 2022
Size: 300 Watt 5/8"Verified Purchase
One person found this helpful
Report