Hydor External Heater Aquariums ETH 200 W Sump and External Filters, Safe and Precise, Tube Diameter 16 mm

I bought this 300watt heater to heat a 340 litre aquarium thinking it might not be powerful enough and that I might need 2 of them. If I take into account substrate, rocks and empty space there’s probably around 280 litres of water. I had it set to 29c to cycle the tank in a room that varies from 15c at night to 20c during the day and once up to temperature (which took over 24hours) it didn’t fluctuate, so it should easily maintain 24c once full of fish. Build quality seems really good, time will tell. I’ve read about people whose heaters have cooked their fish, so I have it connected to an Inkbird ITC-306A dual probe temperature controller which will stop that from happening. It is connected to a Fluval FX4 which was a nightmare to connect as the heater has 16mm connectors and the FX4 has 25mm connectors. With a selection of Y connectors, reducers and Jubilee clips, I was able to split the 25mm return tube into a 16mm for the heater and a 20mm bypass so as not to interfere with the flow/pressure and back to a single 25mm return. After a lot of faffing around it all works perfectly with zero leaks.

Forgive the Title I know its a poor effort at a joke. Now on to the serious business I rid my Juwel aquarium of its standard interior filter and heater,I fitted an JBL CristalProfi external filter and this fantastic external heater, its running now for about two weeks and no leaks or problems,Its quite heavy and needs support in other words don't rely on the tubing carrying the aquarium water to support it,I used a long plastic cable tie which I fed through the loop on the heater and attached with a hook to the top of the aquarium.The temperature control on the heater is precise, and reliable,two important things before I finish when Hydor say a 16 or 12mm hose that is the inside bore measurement of the hose coming from your external filter and because the tubing is a tight fit I found fitting the tubing to the heater first the best way to approach the job.

It worked wonders from day 1 but 6 months in it has failed. ended up overheating and causing a leakage from unit. Lost around 25 litres of water from my tank as its external. Luckily I was in As I have £300 of discus in my tank Could have been alot worse I know it's under warranty but I won't trust to use this product again as many others have experienced same type of faults . Not worth the £80 I paid. Back to the old reliable internal heater it is

Can be excusing keeping an eye on it. Personally I've found it to be unreliable. Does not keep temperature stable

I've never had an external heater before but have kept fish a LONG time. When my latest heater decide to cease functioning without warning (as they do), after running about finding my spare I started looking to see if there was anything new on the market. Well I found this! I bought the Hydor, connected the pipework and set the temperature. Its been great. Temperature is rock solid stable, It makes a small clicking noise whenever it turns on and off, but its nothing that would distract. There is a light on the unit to show when its heating, which goes off when its not. Its somewhat larger than expected, being the size of one of those small plastic cola bottles, and i wonder if i need to clean it internally, but its been great. Finally, make sure you purchase the correct size for your filter pipework and remember you will need to cut the pipe with a stanley knife or similar in order to fit in-line. Very pleased.

Easy to install, quiet and hides away in a cupboard, and easy to operate

Works really well, can be hidden but is quite large and only has a hanging hook on one end which can be a problem. The only thing with this item is that when it switches in, it sends my co2 monitoring computer off of the scale so I have a feeling that there must be some minute electrical leakage into the water as the computer measures mV and this only does it when the water is flowing through it and not when it just switches on and off powered from the same socket but taken out of the pipe work so internally dry.

This in-line heater was quick to install (just cut the pipe going up to the tank from my filter and inserted it) and works great. It's so much better to have this, than have a heater in the tank and have the hassle of having to clean it, putting a guard on it to protect your fish from being burnt and the visual eyesore of having it in your tank. The only thing to be aware of, is that it is heavier than you expect, so you do need to hook it up (via string in my case), so the weight of it and pipework does not risk pulling the pipework appart or away from the tank.

It last for a year until it stopped working. This is not reliable. I don’t recommend for long term.