Hidom Aquarium Heater Quartz Glass Submersible Fish Tank - 100w Thermostat Control Pro-Heat HT 8100 - With FREE Stick on Thermometer - Suitable for both fresh and salt water

UK plug was a bit cheap looking. Shiny hard plastic found in less qualitative devices not complying with regulations.. Packaging contained a foam sleeve to go around the glass. The end cap was loose in the box and didnt fit well. Now the bad part. It's faulty. Set to 24c and noticed within a few hours it was clicking on regularly. Measured with laser thermometer I use against my higher end heaters and it showed 29c as water temperature. I dropped it to 20c setting and within a few seconds it clicked back on. Hidom have a reasonable industry history in fish world. This is a bit poor and would invariably cook your fish in your sleep. Luckily this is just for a quarantine tank and had no fish or plants. Heaters are risky if you buy cheap but with this said always use a laser thermometer against a known source as the markings are not very accurate and it takes a good few hours to really test a heater before adding fish.

I've got two of these and have been using them for several months without issue. They've safely maintained water termperatures and kept them stable, although I have them set to the same temperature and I'm using them in two identical tanks, I found one tank was consistently reading 1 degree higher than the other. I've seen others warn about failures so I've opted to use external regulators to safeguard against cooking my fish if they do ever fail, this helped correct the temperature difference. Other than that, I've nothing bad to report and had no real issues.

It all started so well. Bought it to replace an Ehiem which would not shut off. So in this one went and it was fine through spring and summer. However, now with autumn approaching, I find that the Hidom can’t keep temperatures higher than 24C. No matter how high I turn up the thermostat it cuts out at around 24.6 or so. My fish need it at around 28. Now having to trawl through Amazon and fleabay for yet another replacement.

Tested it all out of water, the light came on, almost burnt my hand soni turned it down and put it in the tank ready to heat it up for some guppy fry that are due anytime and the heater broke. So now I have a cold tank and still nowhere to put my pregnant guppy.I can't even return as I bought a little while ago but I've only just needed to use it so just took it out of the packet.

But that’s all they do, heat the water up. I have had these for a few weeks now on my new tank. Set them up in a bucket and they have been on the tank for 2 weeks. They were fluctuating so I left them alone to let the settle. Last night they broke their own record. Went from 77.4f to 79.5f in a 6 hour window and then back down to 78.2f. No good for marine fish and not to good for tropical I wouldn’t think.

The dial on the side was about 3c lower than actual, that could be compensated for however over the few days I owned this before returning the heater would click off allowing the water temperature to fall 5c below the required temperature and would only start heating again once turned off for a few minutes then back on again. Cheap, unreliable and retuned.

In description saying should be a thermometer sticker as well, but wasn't... I don't find any way to contact the saller to solve the issue,the only alternative is that to send the order back

This is what the heater looked like after 6 weeks use , leaving my fish cold for 2 weeks , as was in the office not currently being used and only returned to service tankPrevious heater this replaced lasted 6 years .