HT Submersible Heaters

Product No. 26447

HT Submersible Heaters is rated 2.1 out of 5 by 110.
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Tetra's HT line of heaters are easy-to-use and work in aquariums ranging from 2 to 55 gallons. The heaters have electronic thermostats that automatically adjust heat output to keep water at a constant 78 degrees F. All HT heaters have indicator lights to let you know when the heater is on, heating the aquarium.

All Tetra HT heaters have red/green indicator lights to let you know when the heater is heating(red) or on standby(green). The low voltage thermostat maintains water at 78°F without any adjustment required. Be sure purchase the correct heater for your tank size. Buying a heater too small for your tank can cause under heating. It is critical to ensure your tank is equipped with a hood or glass canopy to contain the heat inside the aquarium. All Tetra HT Heaters will shut off if an electrical short is detected for your safety.


This product comes in the following sizes:
HT10 (50 watt) - 2-10 gal
HT30 (100 watt) - 10-30 gal
HT40 (150 watt) - 30-40 gal
HT55 (200 watt) - 40-55 gal
Rated 2 out of 5 by from I’m confused I’ve had this thermometer in my tank for 3 hours and it hasn’t changed the water temperature. The red light shuts off after 1 minute of being plugged in. I will purchase another one to see if this problem persists. I have a thermometer in my tank and it reads at a constant 50 degrees Fahrenheit. No green light is on.
Date published: 2018-10-12
Rated 1 out of 5 by from Didn't Work It worked well for about a month then the green light was always on. I monitored the tank temp and the water was not being warmed at all. I tried it in a few of my other tanks with the same result. Very frustrating. I wish I had read the reviews before I purchased this item
Date published: 2018-10-10
Rated 1 out of 5 by from Poor heat regulation Tetra team, I believe you're too quick to dismiss reports of poor performance from this heater. I purchased a HT10 for a small Fluval aquarium to replace a Marineland heater that broke after several years of good service. As others have reported, it does not cycle properly, only holding about 70F. It's going back to the store.
Date published: 2018-10-10
Rated 5 out of 5 by from works great, works great, but just wondering how deep can i put it it in the water?? all the way in? im using a large jar, so wanting to stuff it deeps as possible to leave room for the filter at the top.
Date published: 2018-09-21
Rated 5 out of 5 by from WORKS GREAT SO FAR! My new 6 gallon tank was only at 70 degrees so I installed the HT10. Raised the temperature to 78 degrees within a few hours and has been keeping it there since. No complaints here!
Date published: 2018-09-21
Rated 1 out of 5 by from Horrible I have had the heater for 2 months now and I moved on month 1 when I got to my new house I opened the heater for the 1st time since than the temp stays at roughly 68 degrees the light comes on but this heater does not produce heat and it should be recalled immediately a lot of people will lose the fish that they love!!!
Date published: 2018-08-30
Rated 4 out of 5 by from Just bought it but I need answers Quick question. So if the temp in the tank is 76-78 in the tank, The heater simply shuts off? I just bought it for my betta in a 10 G tank and I dont want him to get stressed because the heater fails so bring up the temp.
Date published: 2018-08-25
Rated 1 out of 5 by from Doesn’t work I’ve kept aquariums for decades. Made the mistake of buying this because I didn’t want to drive to my normal shop. Good price. Doesn’t even turn on. Too bad I threw away the box already. Waste of $20.
Date published: 2018-08-24
Rated 1 out of 5 by from Absolute Garbage As I thought this would be perfect for my 40 gallon tank I bought a 200w version. Indicator only stayed on for about 45 seconds then off for a period of time. Heater is placed next to inlet for filter with plenty of circulation. The heater never brought water temp above 73.1 degrees. Had an old heater, different brand, and ran in tandem. Got the water to the desired 78 and the Tetra still acted the same, lit up for 45 seconds and stopped. Removed the backup heater and water dropped to room temp again, 72.8. Seems the light is just an ornament. Exchanged the heater at walmart as I thought must be faulty. Same result. Absolute garbage. Do not buy. Do not waste your time. Do not risk your fish. DO NOT BUY.
Date published: 2018-08-07
Rated 1 out of 5 by from HORRIBLE My fish tank heater broke over the weekend so I bought this as a replacement. This is the worst heater I have ever used. The red light comes on for about 1 minute and then turns off. I have bettas and other fish that are used to the tank being a constant 82 degrees. Now the tank is super cold and the heater won’t warm it up. I’m very low on money as I had to buy new eye glasses and spent $1,600 on a mechanic for my car. I used what little money I had left and decided to skip out on buying lunches for work this week so that I could keep my fish warm and healthy and it didn’t even work. Wasted $14 that I barely had on junk. Now I have no money, can’t eat at my job, and now my fish are at risk.
Date published: 2018-08-01
Rated 1 out of 5 by from Doesn't heat the water I have had this heater turned on for over 24 hours and the water is still cold. I have never seen the red indicator light turn on and it isn't working at all. I wouldn't spend money on this product.
Date published: 2018-07-27
Rated 1 out of 5 by from Not worth money and time I bought this heater thinking it would be a great heater for the price and the red light comes on only for 30secs. Don’t waste your time or money on this it will just fail you. Would give negative stars if could.
Date published: 2018-06-20
Rated 2 out of 5 by from One Today I bought one and doesn't work light doesn't say on the heater not good
Date published: 2018-06-17
Rated 1 out of 5 by from Sucky customer service I contacted customer service to ask about how my heater was malfunctioning, as it was keeping the tank water at 73 degrees instead of the promised "constant 78 degrees". Instead of any help, I was told that 73 degrees was actually normal for the heater, and completely fine for "tropical fish". Problem is, I have bettas. Anything under 78-80 degrees makes them stressed, and it can kill them. TLDR- Heater is malfunctioning, and customer service tried to tell me 73 degrees was okay for betta fish.
Date published: 2018-06-14
Rated 1 out of 5 by from Just Bought One I just bought the 50w and it doesn't seem to stay on. I plugged it in and the light turns on for a minute and turns off.
Date published: 2018-06-12
Rated 1 out of 5 by from Bought a 2nd heater I have one heater for my 10 gal tank. I could not get it past 74. Purchased a second of the exact heater and still 74. Crazy! I can’t get my temp where it needs to be even with 2 heaters
Date published: 2018-05-16
Rated 1 out of 5 by from Failed :-( Was good while it lasted... After about 3 years of sporadic use, it over heated the tank by 10°C!!! Hopefully my betta survived..
Date published: 2018-05-10
Rated 3 out of 5 by from Works great for fish It works great for my betta but my dog chewed my extra one and I don't know what was inside the glass
Date published: 2018-04-25
Rated 2 out of 5 by from Not heating I bought this heater a week ago, but I don’t feel like it’s doing it’s job. It says it’ll maintain the temperature at 78 however mine has not gone past 76. Should I be worried? Is my betta okay with that tempature? Any feedback would help
Date published: 2018-03-25
Rated 1 out of 5 by from Isn’t heating water up I have had this 100w turned on for two days in a 10 gallon tank with 8 gallons of water. My digital thermometer reads 66 degrees. The lights are turning on but it’s not going any higher than 66 degrees. I keep my house at 68 so with the larger heater and not being a lot of water something seems to be wrong with the heater.
Date published: 2018-03-22
Rated 3 out of 5 by from Don't heat up the water!! I bought the heater about a month ago. Light comes on but is not heating up the water!! I have a covered tank. I had the same heater before worked fine. Until I broke it cleaning the tank. But this one is not working at all!!....
Date published: 2018-03-01
Rated 5 out of 5 by from I’m a wh master. I bought this and I’m so happy that my heater is working just fine. But I don’t like it when the glass breaks. Plus I have 14 water heaters in my collection.
Date published: 2018-02-13
Rated 4 out of 5 by from Awesome Customer Service I have had an aquarium for 5 years. And a little over 2 years ago, I got into the hobby of aquascaping (5 gallons and 65 gallons). The heater in my 65 gallon tank is over a decade old and it is working just fine. The 50 watt heater I purchased 2.5 years ago (HT10) was not working properly. I saw 1/4 of my 5 gallon tank's water evaporated in less than 1 week time. I quickly did temperature check and it was in the mid 90 degrees F. Thankfully none of my inhabitants died. I did a quick water change to cool down the water and cleaned the heater just so that there was no buildup around the temperature sensors. I put it back in the aquarium and monitored the temperature for the next 3 hours. It passed 85 degree mark and I unplugged it. I bought this through Amazon 2 years and 6 months ago so I had the receipt. I decided to still contact Tetra to let them know the issue and see if they can help me troubleshoot the problem. Just today, I got a mysterious box in the mail and it was HT10 from Tetra. I never thought they were going to honor the warranty as it was past the 2 year mark. I already bought another brand heater, but I will keep this as a back up heater. Thank you Tetra. Maybe the heater I had was from a bad batch. Hope this one will last a long time. When it comes to electrical and mechanical equipment, some will last long and some will fail quickly, but what the company does for their customer really sets a company apart from others. I trully think that Tetra cares alot for their customers. If I were to give honest rating just for the heater; it will be 2 stars. However because of their exceptional customer service (replacing an item that is past the warranty period), I gave them extra 2 more stars.
Date published: 2018-01-19
Rated 4 out of 5 by from Good Customer Service I have had an aquarium for 5 years. And a little over 2 years ago, I got into the hobby of aquascaping (5 gallons and 65 gallons). The heater in my 65 gallon tank is over a decade old and it is working just fine. The 50 watt heater I purchased 2.5 years ago (HT10) was not working properly. I saw 1/4 of my 5 gallon tank's water evaporated in less than 1 week time. I quickly did temperature check and it was in the mid 90 degrees F. Thankfully none of my inhabitants died. I did a quick water change to cool down the water and cleaned the heater just so that there was no buildup around the temperature sensors. I put it back in the aquarium and monitored the temperature for the next 3 hours. It passed 85 degree mark and I unplugged it. I bought this through Amazon 2 years and 6 months ago so I had the receipt. I decided to still contact Tetra to let them know the issue and see if they can help me troubleshoot the problem. Just today, I got a mysterious box in the mail and it was HT10 from Tetra. I never thought they were going to honor the warranty as it was past the 2 year mark. I already bought another brand heater, but I will keep this as a back up heater. Thank you Tetra. Maybe the heater I had was from a bad batch. Hope this one will last a long time. When it comes to electrical and mechanical equipment, some will last long and some will fail quickly, but what the company does for their customer really sets a company apart from others. I trully think that Tetra cares alot for their customers. If I were to give honest rating just for the heater; it will be 2 stars. However because of their exceptional customer service (replacing an item that is past the warranty period), I gave them extra 2 more stars.
Date published: 2018-01-19
Rated 1 out of 5 by from Hasnt warmed up the tank yet. I bought it a couple days ago and the water is still room temperature (slightly chilled since it’s a cold winter). It is submerged like it needs and plugged in. There is no reason for it to not work. The red light turned on for 30 seconds and has never been on green. It usually has no light on.
Date published: 2018-01-08
Rated 2 out of 5 by from Too hot I brought the heater for my 20 gal tank the first few days it worked perfectly now after two weeks I’ve had readings up to 82.6 and 82.3 now I have come home to a 83.8 tank luckily I came home to check it and turned it off
Date published: 2017-12-31
Rated 1 out of 5 by from Dieing fish I had bought this heater not once my Twice I'm very disappointed with it, not only that but super freaken angry. This heater killed about $39 dollars worth of Mollies all young ones and two adults, the tank had gotten cold Dearing this time of winter, the heater kept turn on and off until it completely turned off, now thanks to that I had to empty out my fish tank of dead fish, this product doesn't help at all so much for my fish...
Date published: 2017-12-28
Rated 3 out of 5 by from Help? Hey, I bought this today and the heater's red indicator light keeps turning on and off? My thermometer says that the temperature's near 70 F and everything so it might be working? but I haven't gotten a green light. What should I do?
Date published: 2017-12-26
Rated 1 out of 5 by from DONT BUY I got one of these yesterday for my 10 Gallon Nano Reef tank, let it rest in the tank over night to adjust to the temp of the water (60-70F), plugged it in a few hours ago only to have it plugged in maybe 20-30 minutes when it shot apart so now my freshly set up saltwater tank smells like burnt rubber and the black granules in the heater is now in my tank...
Date published: 2017-12-22
Rated 1 out of 5 by from One is great other is aweful I have several of the HT10 to heat a few of my smaller tanks and they honestly are a craps shoot. one or two do great with the tank keeping a consistent temperature right on the nose in the typical tropical fish zone of around 78 degrees but I have one or two more that just can't get the same size tanks up to the same temps. Even tried swapping to see if the set up was the variable.. Nope, heater just doesn't get up to temp even though it is turning the heating element on. Really disappointed since the others are performing so well.
Date published: 2017-12-15
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