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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
16 ounces
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

Customer reviews

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

Customers say

Customers like the temperature and ease of installation of the pet supplies. For example, they mention it's easy to install and set up. That said, some complain about the durability. Opinions are mixed on efficiency, quality, leakage, size, and accuracy.

AI-generated from the text of customer reviews

162 customers mention118 positive44 negative

Customers like the temperature of the pet supplies. For example, they mention it's keeping the temperature where they want it, it'll heat their tank consistently and efficiently. Some say it'd be the best heater for lifetime sakes, and it' a very efficient way to heat a tank. Overall, customers are satisfied with the temperature.

"...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

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

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

42 customers mention31 positive11 negative

Customers like the ease of installation of the pet supplies. They mention that it is easy to install inline with the filter, and it works consistently and quickly. Some say that it takes a few minutes to connect.

"...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

152 customers mention100 positive52 negative

Customers are mixed about the efficiency of the pet supplies. Some mention that it worked well, while others say that it just quit working. The simple temperature rotor-dial works perfectly. However, some customers say that the wattage is overkill for a 12 gallon tank.

"...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

"...Definitely would recommend that.Initially, it didn't want to work plugged in the inkbird but would if plugged into the wall...." Read more

"...thermostat and heating work fine for me. 75 gallon tank (200W is low but i have another heater that assists)...." Read more

67 customers mention29 positive38 negative

Customers are mixed about the quality of the pet supplies. Some mention it's reliable and well constructed, while others say it failed catastrophically.

"...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

"...via aftermarket heat-controller; it heats fine but their analog thermostat is garbage.Review on Feb 8, 2012.... 5 out of 5 stars...." Read more

"...it run, and get temps adjusted, and I'm happy to say it is very reliable at holding them which is all that I can ask for in a piece of heating..." Read more

33 customers mention17 positive16 negative

Customers are mixed about the leakage of the pet supplies. Some mention that it fits snugly and does not leak water, while others say that it started to leak after about 4 months. Some customers also mention that the tank had a crack in it and water had leaked out the back.

"...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

33 customers mention15 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, and it fits snugly. However, others say that it is rather large, unflexible, and takes up significantly more space than a submersible would in volume.

"...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

26 customers mention15 positive11 negative

Customers are mixed about the accuracy of the pet supplies. Some mention that the thermometer is pretty accurate, while others say that it's not accurate at all.

"...It does keep the temperature very even and consistent according to the setting...." Read more

"...The one downside is the temp dial is very hard to read and is not 100% accurate...." Read more

"...Working for a month now in an unheated room and it is dead accurate and does not fluctuate...." Read more

"...It still heated if I turned it all the way up but it was no longer accurate and I just unplugged it just to be safe...." Read more

48 customers mention0 positive48 negative

Customers are dissatisfied with the durability of the pet supplies. They mention that it failed within a few months of installation, broke within 1-2 weeks, and malfunctioned. Some customers also report that the wire on the inside and some poor components.

"...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..." 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

"...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

"...Both units showed evidence of prior misuse. Both power conduit strips were fried, and many of the individual resistor strips along the glass tube..." 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
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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
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