Search  for anything...
FREESEA

FREESEA 100 Watt Aquarium Fish Tank Heater with Aquarium Submersible Thermometer

    • Based on 9,960 reviews
Condition: New
Checking for product changes
$25.99 Why this price?
Holiday Deal · 41% off was $43.99

Buy Now, Pay Later

As low as $6 / mo
  • – 4-month term
  • – No impact on credit
  • – Instant approval decision
  • – Secure and straightforward checkout

Ready to go? Add this product to your cart and select a plan during checkout. Payment plans are offered through our trusted finance partners Klarna, PayTomorrow, Affirm, Afterpay, Apple Pay, and PayPal. No-credit-needed leasing options through Acima may also be available at checkout.

Learn more about financing & leasing here.

Selected Option

Free shipping on this product

This item is eligible for return within 30 days of receipt

To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

Availability: In Stock.
Fulfilled by Amazon
Arrives Tuesday, Dec 24
Order within 7 hours and 41 minutes
Available payment plans shown during checkout

Pattern Name: 100Watt


Features

  • 100 Watt Heater: This Aquarium heater is suitable for 15 to 25 gallons aquariums, Length - 13.5 inch,voltage 110-120V, power cord is 4.0 ft, please choose the right wattage aquarium heater according to our size chart.
  • Temperature range: 63F~95F , It is very easy to adjust the temperature you need, we also deliberately give each customer a free diving thermometer, you can observe the water temperature of the fish tank at any time.
  • Intelligent temperature control:Automatic constant temperature function, when water temperature reaches to specified temperature value, heater will automatically stop heating, when water temperature is lower than the set temperature, heater will automatically start heating. Furthermore, Automatic safety shut-off feature, and overheating protection.
  • Explosion Proof:Note: 1. Aquarium heater is 100% submersible use only, during its heating time, heater must be 100% submerged into the water.,Please unplug the power supply when cleaning the fish tank or aquarium water changes. 2. Heater rod is suitable for people over 16 years of age. Children or minors should be under adult guidance or supervision. Thickened quartz glass,can be used in fresh water and salt water aquariums,easy to hide in the tank.
  • SATISFACTION GUARANTEEDGain the confidence to go hard with us! Our Aquarium Heater is built with durability in mind and safety for every design, In the remote possibility that youre not satisfied with our product, just contact us, and we will gladly give you a new Aquarium Heater replacement. 12 Month Warranty and 24 Hour Professional After-sales Service.

Brand: FREESEA


Color: Black


Age Range (Description): Adult


Outer Material: Glass


Product Care Instructions: Hand Wash Only


Power Source: Corded Electric


Item Length: 13.5 Inches


Upper Temperature Rating: 95 Degrees Fahrenheit


Reusability: Reusable


Resolution: High Density


Product Dimensions ‏ : ‎ 48 x 0.99 x 0.2 inches; 10.55 Ounces


Date First Available ‏ : ‎ June 9, 2019


Manufacturer ‏ : ‎ FREESEA


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Dec 24

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

  • Klarna Financing
  • Affirm Pay in 4
  • Affirm Financing
  • Afterpay Financing
  • PayTomorrow Financing
  • Financing through Apple Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • Certainly not the best option
Pattern Name: 25Watt
I purchased this heater for a new aquarium project. The tank was an Aqueon 5 Gal Mini Bow and the concept was to introduce a male betta and a small number of compatible tank mates. Using live plants as decoration and to help with water condition. Since the tank population, after the initial fish introductions, to be stable, I wanted to avoid the use of medications and would be using an UV sterilizer if Ick or other diseases were contracted. Maintaining a constant water temperature was an important part of the scheme so I looked at the available small heaters. I decided against using an unregulated heater or the ones that are preset an non-adjustable. I chose the FREESEA 25 Watt submersible heater, primarily because of it's compact size and the fact that it had an adjustable temperature control. The included thermometer was a bonus. I was aware of the multiple reviews complaining about over temperature and poor regulation but, I could see that the common thread here was that the temperature dial markings did not correspond to the real temperature settings obtained. Many reviewers were happy with the purchase so I forged ahead. i also purchased a different heater as a backup. In retrospect, that was a good decision. I setup the tank using the included power filter and introduced the Betta and 5 small Glowlight tetras on the first day. I followed 2 days later with 3 Neon tetras and that basically completed the setup. The heater was well packed and just the right size for the tank. I did notice that, when setting the initial temperature, there was quite a lot of free-play in the settings knob before the indicator light on the heater would turn on or off as the results of your input. I other words, you could turn the knob, as much as, a 1/8 turn in each direction before the heater would turn on or off. If you had been looking at the markings, that meant you could go from 73F to 84F without any effect on the heater. That was disconcerting. I expected it to react right away and allow confirmation that you had made a change on the temperature settings. At the end, I went for the middle of the free-play range and left it there. I checked over the next couple of days and the heater was able to maintain an indicated temperature of 79.8F throughout the whole day and properly compensated for the AC cycling etc. On day 3, I noticed white spots on one of the Neons and immediately implemented my emergency plan. I removed the power filter and replaced it with the 3 Watt Green Killing Machine UV sterilizer. So far the plan is working, initially the white spots spread to the Betta and a couple of the Neons but, the Ick infection is now under control and currently there are no more spots on any of the fish. I'll wait another 2 weeks to insure that the parasite has run through it's life cycle and then remove the UV light. Back to the heater report. Around day 2, I noticed the formation of a film on the surface of the water. I promptly removed it (paper towel applied to the surface method) and kept my eye on it. The film was not oily but instead, it looked like l a thin solid surface contamination. When I picked up with the paper towel, it left small fragments floating. Think miniature broken up ice field on the ocean.... Anyway, since I had introduced a brand new heater and UV sterilizer one or both of them could be releasing mold release or plastisizer from their many plastic parts. I figured it was a temporary thing and it would go away on its own. As the days went on, the film on the surface problem got worse. I had to clear it often. I was in the process of installing other digital thermometers I had purchased to test them ( more on that later) when I noticed that the top cap of the heater had a substance growing on it. There was a translucent layer about 1/4 inch thick all around the black upper cap of the heater. The substance was gel-like and slimy. It also had a foul odor to it. I removed the heater and scrubbed the cap to remove the material. I put it back in the tank and also upped the temp just a touch to shorten the Ick cycle. The next day the temperature had shot up to 84F. That is at least a 5 degree change for was a minimal turn of the temperature control knob. After re-visiting the reviews on the heater, I decided not to take more risk and pulled the heater out of the tank. When I had the heater out I noticed that in just 24 hours, the upper end cap was already coated with the foul slimy substance. Not good! Oh yeah, the thermometer. I purchased a lot of three AQUANEAT digital thermometers, around the same time as the heater. These units are essentially identical to the FREESEA unit that came with the heater. When they arrived I went ahead and installed on the tank to test them and they were all within .3F degrees of one another. The FREESEA thermometer read at least, 2 degrees higher than all the others. If you search the reviews on this site you'll see all of the complaints about how difficult it is to reliably set the temperature on this heater. Someone else experienced the surface film problem and the slimy coating on the heater end cap. He posted a picture of the condition. It looks just like what happened to mine. I can confirm both of those problems. While it was possible for the heater to maintain what I now know to be about 77F or so, I can't imagine having to be concerned that a small touch of the temperature control raise the temp by 5 degrees or more. This one is not for me. It's not worth the risk. As for the thermometer, it would have been nice if it was more accurate. I can't vouch for the battery life or its reliability, since I've only had it for just a few days. I only turned the thermometers on when I needed to check the temperature. Under those conditions, it might be a long time before the battery needs replacement. Hopefully you'll find these comments helpful. I'm disappointed it didn't work for me. ... show more
Reviewed in the United States 🇺🇸 on December 7, 2020 by Rod M.
    • Update- after 1st came broken. ReviewUPDATE will be for weeks of use, not just out-of-the box.
Pattern Name: 25Watt
Review Image by Andres Andres
UPDATED: After having this replaced and functioning for a week, I feel I can give a fair review now. I raised from 3 to 4 stars. 5 stars if what the setting I leave it own is consistent. In my 8 gallon, I think it's perfect, however to give it a fair assessment, I thought I'd see where it stabilizes and as it's tweaked for the first 48 hours. The temp I want is 80F. After it stabilized at 78F, I gradually raised it. Mind you, the dial is on almost 90F for it to stop there. Then, gradually I raised it and achieved 80F to 80.5F which made me happy for about 3 days. Without any changes in the whether, nor lights on in my tank, nor change in the temp inside my house (which is set to 75 now in winter) this thing started jumping up the temp. First I saw it go up to 81 from morning to late night on the 6th day (3 days after reaching the constant 80F I wanted.) I though nothing of it. The next morning it was in the low 82s. It got my attention. By night that day I saw it read 83F and I started to panic. There was nothing I changed, and the tank is clean of algae and all. So why the sudden spike? I don't know. Needless to say I was stuck monitoring it all day as I had to again adjust the dial. Bringing it down back to 80F (with having to adjust the dial back down to the 80s, and gradually back up to almost 90.) It's been 80ish for almost 2 days. I would just recommend that this be monitored closely the first week. Also, don't trust that whatever temp you set it on will be the temp it will auto stop on. It doesn't seem to know if the temperature it's set to has been achieved. Had I not intervened, my fish would be dead. I'm happy that its keeping the water from spiking to the low 70s for my betta. But I'm bit too thrilled that I still had to out hun through getting to a nice warm temp and normalizing, then getting hotter on it's on, and then having to being the temp of the water back into the 70s to get it back to a constant 80. So far, it's at 80ish. Works, but needs tweaking and monitoring. And atleast the replacement disnt come with a broken bulb like the first one initially did. That's an honest review. OP: I bought this to heat my small tank almost as an emergency. The description is perfect and exactly what I need, however, the glass was broken. Amazon told me this is a 3rd party and they can't expedite it, but they'll replace it since it's under 20 bucks. I'll see if the replacement arrives when and as expected. BIGGEST Concern: Now, I'm forced to wait another 3 days with my Beta cold, and in order for me to keep him warm I have to have the heater on in my house 24/7 so the temp stays consistent. Needless to say, this makes sleeping at night for us very uncomfortable as we are used to having the AC on at 65, or when its winter like it is now, we just keep the AC off since it gets cold naturally. It was packaged well from the Seller, as you can see- the glass tube even has a protective foam sleeve over it, and the whole unit is inside a fairly sturdy box- however, the main packaging it arrived in was an envelope instead of an Amazon box. Amazon boxes have 2 extra layers of protection- the cardboard, and the bubble wrap. I recommend the buyer chip in a little extra, to make sure Amazon packs anything with glass, in a box and not these yellow envelopes. As for the unit, it's now an electric rod that will electrocute anything since it plugs directly into the 120V outlets. It's going in the trash, and the cheap little thermometer is going to just be an extra one in case the other one breaks- because I'm seeing a lot of reviews of it being the main thing that breaks or malfunctions quickly. * I will change my review and update upon delivery if it arrives as was told to me, and after I've used it a while. REVIEWS here are based on the immediate results seen after people use it, but only in the first 24 to 48 hours, usually. I don't think that's a fair assessment of ANY product. Reviews like, "Plugged it in and works!" or "Put it in my tank and it heated up to the temp I programmed it for," don't really say if it works correctly- and most importantly if it lasts a decent amount of time. I'll update mine after having it a couple of weeks, because that's what we REALLY want to know- not that it works out of the box, but that it does what it says once in use for a while. ... show more
Reviewed in the United States 🇺🇸 on December 13, 2020 by Andres Andres
    • Efficient and Affordable
Pattern Name: 25Watt
The item does what it should. It was a very easy set up. Extremely affordable. Was actually highly recommended by an expert in setting up/maintaining tanks. I’m glad I took his advice and made the purchase. So far so good. Certainly cheaper and better quality than anything we could have gotten from our local pet stores. ... show more
Reviewed in the United States 🇺🇸 on June 14, 2023 by Efficient and Affordable

Can't find a product?

Find it on Amazon first, then paste the link below.