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The Cobalt Neo-Therm is one of the most popular submersible heaters on the market.
And if you are here, you have one question on your mind:
Table of Contents
Is this heater any good?
Well, you have come to the right place. Today, I am going to take a detailed look at this aquarium heater and whether it’s worth your hard-earned money. (Spoiler, it’s pretty great.)
Already decided you want this heater? Buy it here…
With that out of the way, it’s time to jump into my review.
Specifications
Don’t have much room to spare? Use the following table to determine if the Neo-Therm heater will fit inside your aquarium.
| Size | Tank (up to) | Length | Width | Height |
|---|---|---|---|---|
| 25w | 6 gal | 6.55″ | 2.2″ | 0.88″ |
| 50w | 12 gal | 6.55″ | 2.2″ | 0.88″ |
| 75w | 20 gal | 6.55″ | 2.2″ | 0.88″ |
| 100w | 29 gal | 9.72″ | 2.2″ | 0.88″ |
| 150w | 40 gal | 10.9″ | 2.2″ | 0.88″ |
| 200w | 50 gal | 10.9″ | 2.2″ | 0.88″ |
Note: All measurements of the Neo-Therm heater are taken at the longest point when resting in the mounting bracket.
The following specifications remain constant no matter which model of Neo-Therm heater you buy…
| Country of manufacture | Poland |
| Power cord length | 6.5 foot |
| Temperature range | 66 – 96°F |
| Max operating depth | 31.5″ |
| Outer casing | Plastic |
What’s in the box?
Inside your Cobalt Neo-Therm box, you will find…
- 1 x Cobalt Neo-Therm heater
- 1 x mounting bracket
- 2 x suction cups
Oh, and an instruction manual. Read it before setting the heater up in your tank!
Design
The first thing you will notice about the Cobalt Neo-Therm heater is its unusual looks. I think it’s fair to say that this heater doesn’t look like any other on the market.
This heater looks sleek. Yet ugly.
The all-plastic design definitely isn’t going to win any beauty pageants. But hey, it’s shatter-proof. If you drop this heater on the ground, it’s not going to break into a million shards of pain, unlike those glass aquarium heaters.
But where the Neo-Therm’s design really stands out is just how thin it is.
It’s like someone went at an aquarium heater with a rolling pin and the flattened Neo-Therm is the result. Fantastic because it won’t roll off your counter during those occasional cleanings.
Cobalt did an amazing job at creating a heater that is just 1/3″ wide at its thinnest point.
Funny enough, when looking at the Neo-Therm front on, this design makes it look wider than every other aquarium heater.
However, the flat design allowed Cobalt to knock a few inches off, making it one of the shortest heaters around. As you see in the photo below, the shorter length was particularly noticeable in 150W+ heaters.
So, thinner and shorter but thicker when you look at it front on…
But don’t worry, even though it looks like there is more heater to love, the matt black plastic doesn’t draw attention when placed under water. In fact, I was surprised at how well the heater blended in with the black background of my aquarium. If it wasn’t for the light-up temperature display, I wouldn’t notice it at all.
The temperature display sits at the top of the unit and ranges from 66 – 96°F in increments of two.
I cover this display in more detail in the next section.
The final point of interest is the mounting bracket:
This simple piece of plastic attaches to the glass of your aquarium via two suction cups.
Simply slide your Neo-Therm heater inside, and the bracket holds it in place.
It may be simple, but it’s definitely functional.
Ease of use
The temperature display of your Neo-Therm heater bursts into life the moment you plug it into your powerstrip.
It might look confusing, but it’s actually very simple to read.
If the water is hotter or colder than the set temperature, two lights display. The flashing light indicates the water temperature while the solid light indicates the heater setting.
The light will flash slowly if the water temperature is less than the temperature setting of the heater. If the water temperature is hotter, the light will rapidly flash to indicate that your water is too warm.
When the heater setting and water setting are the same, only a single light displays.
This unusual method of displaying the temperature may take some getting used to if you are coming from the dial-type aquarium heaters. I know it did for me.
But it didn’t take before I could check the temperature of my tank with just a quick glance. I actually appreciated not having to peer over the top of my aquarium just to see the temperature setting.
When you turn the Neo-Therm heater on for the first time, the temperature will be set at 78°F. If that’s the right temperature for your tank, then that’s all you need to do.
But if you want the temperature higher or lower, you must adjust it. And to do that, use the small button located at the top of the heater.
Each time you press this button, the setting light moves one space clockwise. So, if I need to change the heater from 78°F to 76°F I must press this button 15 times.
It’s definitely not as easy as twisting a dial. And to top it off, the button is a little stiff.
At first, I didn’t like it. But then I tried to think back to the last time that I actually changed the settings on my aquarium heater. I honestly couldn’t remember!
That’s exactly why this crude system isn’t a drawback at all. Once you set the temperature the first time, it’s unlikely that you will adjust it again. And, the stiff button makes it difficult to change the temperature by accident.
And, the heater has a built-in memory. If you unplug the heater or there is a power outage, you will have the correct temperature when you power it back on.
As for placement, I had no issues mounting the Neo-Therm horizontally or vertically. The suction caps of the mounting bracket held tight for the duration of testing.
Accuracy
I don’t need to tell you… If an aquarium heater isn’t accurate, then it’s as good as useless. You are essentially trusting this thing with the lives of your fish.
So to test the Cobalt Neo-Therm’s accuracy, I brought in the big guns…
I wanted to be confident in my review, so I tested using the following equipment…
- Flir Thermal Imaging Camera
- Fluke Digital Thermometer and Thermocouple Probe
- SP Scienceware Liquid Thermometer
All calibrated with NIST certification.
Cobalt claims that their Neo-Therm thermostat is accurate to ± 0.5°F. That means that if the digital display shows 78°F, then the water temperature could actually be 77.5°F or 78.5°F.
So, how did their claims hold up to real-world testing?
Actually, pretty darn good.
Out of the full range of Neo-Therm heaters tested, no heater was out more than 0.2°F. That’s even better than their claim and makes the Cobalt Neo-Therm one of the most accurate aquarium heater on the market!
If you want an aquarium heater that keeps your water temperature stable, look no further.
Setting Up Your Cobalt Neo-Therm Aquarium Heater: A Step-by-Step Guide
Got a new Cobalt Neo-Therm heater? Great choice! Let’s get it set up so your finned friends can enjoy a cozy, warm home. Here’s how you do it:
- Attach the Suction Cups: Your Cobalt heater comes with handy suction cups. Attach these to the mounting bracket. This is where your heater will snugly fit.
- Slide the Heater into the Bracket: Now, gently slide your Neo-Therm heater into the bracket. Ensure it fits securely at the top, right near the thermostat.
- Submerge Your Heater: It’s time to let your Cobalt heater take a dive into its new aquatic world. Remember, Cobalt aquarium heaters need to be fully submerged to work their magic properly.
- Choosing the Perfect Spot: When placing your heater in the tank, avoid areas with dense algae growth. Also, ensure the heating element isn’t touching gravel or decorations. A clear area along the tank glass or in the sump is ideal.
- Secure It in Place: Use those suction cups to firmly attach the heater to your aquarium’s glass. It’s all about stability and safety.
- Patience is Key: Wait for about 15 minutes before powering up your heater. This gives it time to acclimate to the water temperature.
- Plug It In Safely: Keep an eye on the LED indicator as you plug it in, creating a “drip loop” in the power cord for safety. This avoids any potential water-related electrical issues.
- Set the Temperature: Time to dial in that perfect temp. With the Cobalt Neotherm heater, each button tap ups the heat by 2°F. Adjust until you hit your tank’s ideal temperature. Overdid it? No worries, just readjust until you find that sweet spot.
- Monitor and Adjust: Keep an eye on those LED indicators. They’ll show you both the set temperature and the current water temperature.
And there you have it! Your Cobalt Neotherm heater is all set to keep your aquarium at the perfect temperature, ensuring your aquatic buddies are living in comfort.
Should you buy it?
I actually loved the Neo-Therm aquarium heater.
It’s not the prettiest thing you’ll ever see. But you know what? It doesn’t need to be.
It just sits there, blending into the background of your aquarium, quietly heating your water.
While it has a few quirks, namely in setting the temperature, this one-off job is hardly a deal-breaker.
Accurate and reliable, it’s everything you want in an aquarium heater.
Just make sure you shop around because these heaters vary dramatically in price. At the time of writing, the cheapest place I saw them was on Amazon.
Highly recommended.
I give it 4.8 / 5 starfish.
What do you think of the Cobalt Neo-Therm aquarium heater? Let me know in the comments below!
I mostly agree with this review. I don’t like that although it is thin, it looks bigger than other heaters because I have mine on the back of my tank and look front on. Really, the thin side should face the front of the tank.
Good heater. I’ve had it for 2 years now and my discus are happy.
Hi Jamie,
Thanks for the feedback. You bring up a good point about the appearance of the heater!
I have had 3 of these fail in less than 1 year. I want to love them but with the high failure rate I will pass.
Hi Rob,
Thanks for your feedback, have you contacted cobalt to confirm that these were authentic? That failure rate seems too high, I have 7 people in my fish club using these in multiple tanks without failure. what heater do you suggest instead?
I did not contact them. I just started using the ehime jager and have been using the same one for about a year and a half with no issues. But as always use what you like and works for you.
Hi Rob,
If it’s not too late, I highly recommend reaching out to them, they have great customer service, you might be able to get a refund? Three neotherms would add up. Good choice! Jager is another I highly recommend, it actually used to be my go-to heater, the only reason I prefer the Neotherms is because they take up less room in my tank and blend better into the background. I’m really happy to hear they are working well for you. I completely agree with sticking to what you like and works!
Ian,
I had a Cobalt 100 get pretty “algaed” up. What’s the best way to clean this? This is my first go-around with this product and I want to do this right.
BTW-I am a Jager user for many years so I know how to maintenance my glass heaters.
Thanks-
Marie
Hi Marie,
What sort of algae are we talkin about? If it’s just the soft mushy stuff, I can remove most of it with a few back and forth swipes with a sponge.
I appreciate this review and agree with all of it for the most part. I use these in my smaller tanks because of the slim design and that they are black and blend in as you stated. I also appreciate that they are plastic because when you’re cleaning a small tank you do have a tendency to knock things around a bit.
My only issue with these, and I have used 4 over the past year and a half, is that the button to change the temp is extremely difficult to push, as you also stated but in addition they all have had failed light indicators. Oddly enough it always seems to be the 76 and 78 degree lights which is pretty much where I keep all of my tanks heater settings. I can however continue to push the button and if you pay close attention you will notice while light is moving so that when you hit the 76 or 78 degree spot you pretty much know you’re there even though there’s no light. Still stinks though because if the button isn’t working well then you may not actually be sure and for this price point for a 25 or 50 watt heater it kids tics me off. I have had to return one as it failed completely but they sent me a new one no questions asked so that’s a positive in customer service for sure. I now have one that I can’t change the temp at all but I always use an ink bird so that’s my fail safe.
Lastly, my temperature button is on the front of my heater directly in the middle of the light indicators not on the top. Probably just an old design but I’m hoping to order a new one with the temp change button on the top, I believe it will be far easier to use.
Thank you again for this review but I do hope that one day I will find a slim low profile heater with as much accuracy as the cobalt for a better price.
Thank you so much for such a thoughtful and experienced take! You’re clearly speaking from real hands-on use, and we truly appreciate the time you took to share all this. The slim profile and shatterproof plastic are definitely standout features, especially for smaller tanks, but we totally hear you on the frustrations with the stiff temp button and those unreliable indicator lights, especially when they fail right at that 76–78°F range that so many of us rely on. That would drive anyone a little nuts.
It’s really helpful to know the newer design may have moved the temp button to the top. We’re hoping that’s a sign of improved usability, and we’ll be keeping an eye on future models too as we continue testing and updating our gear reviews. And major kudos for using an Inkbird as a backup, that’s such a smart and safe choice, especially when heater reliability gets shaky.
If you ever find that perfect slim heater with great accuracy and an easier interface, please let us know. We’re always looking too, and we’d love to share a better option with the community!