Hagen Marina Betta Submersible Heater for Aquarium

I would have rated this heater 5 stars had the company not put so much thought into a deliberately deceptive, albeit technically accurate description.

First, and most important to realize, is that this is an always on heater. It has no thermostat, it simply warms up and stays warm all the time. So the statement that it "reaches a preset temperature" is extremely misleading since most will interpret that to mean the water temperature, when in fact it's the HEATER temperature that remains constant. Whether or not it keeps a bowl/tank at a desired temperature depends on the tank size/water volume, temperature of the room, amount of water circulation/movement, other heat sources such as a light being on or off, lid or no lid, acrylic or glass container, heater placement, and so on. All small "Betta" or "bowl" heaters work this way.

This is an 8 watt heater. These heaters usually run between 7.5 to 15 watts. If you have need of the higher wattage, it's much better to use two 7.5 than one 15 watt. That way just one can be unplugged if the water temp is too high, giving you a bit more flexibility. They can be safely buried in the substrate, a nice option in some set-ups.

This particular heater has a small red LED, which the description states is lit "when the heater is working" a technically accurate but also deceptive statement. It should more truthfully state that the light is lit whenever the heater is plugged in, rather than give the impression the light, and therefore the heater, will cycle on and off. Rest assured, it won't. No matter the temperature of the water, the heater will emit 8 watts worth of heat anytime it is plugged in.

Using this type of heater requires careful and ongoing monitoring. An accurate thermometer is a must. You cannot rely on charts/claims as to how many degrees a specific size heater will raise the temperature in a specific size tank, there are far too many variables. Still, these little units can be quite effective, and I do like this one quite a bit. The LED light, though possibly intended as more a marketing ploy than anything else, is actually a nice feature since there may be times you will unplug the heater and it's easy to forget to reconnect ones with no such indicator. The weight is nice, it tends to stay where it's put, thinner/lighter models are easily displaced. On identical tanks they seem to be very consistent.

It is entirely possible to seriously overheat a bowl or small tank using this type of heater. That is not a malfunction, it is simply an inherent risk with any always on heater. If the room gets warmer, the water will as well. These heaters do not adjust for any variable, they simply continue to emit the same amount of heat no matter what. That is what most people having problems with them don't realize, and what the cleverly worded descriptions fail to make clear. When the room temperature changes, so does the tank temperature. These heaters merely keep a small volume of water a few degrees warmer than it would be without it. They do not and cannot maintain any tank at a specific temperature, ignore claims of "maintains ideal temperature" as they are patently false. The aquarist has to be the thermostat by matching tank size to heater size (wattage) and continually monitoring fluctuations due to changing room temperature and other variables. These heaters are not for overly sensitive species, but it is probably far better for a Betta to be in water that fluctuates between 75° and 85° than in unheated water fluctuating between 65° and 75°. Bettas are heat loving fish and quite tolerant of even very high temps, which makes using this type of heater less risky but still not foolproof.

For around $20 or more, a heater controller can be attached. I have a rack of 9 identical small tanks w/9 of these heaters connected to one power strip that is plugged into a single controller set at 82°. The probe for the controller is in one of the 9 tanks, and this works fine, keeping all of them a steady 82°.

As I stated at the start, the actual heater is nice quality and has proved quite consistent from one unit to another. It performs exactly as it should, and the limitations are not flaws, just inherent with what it is. I'm not certain why the description only rates this 8 watt heater for up to 1.5 gallon tanks, but it's relatively meaningless in any case. Some of the 7.5 watt models are recommended for tanks "up to 5 gallons" which is no more validit depends entirely on the sum of all the variables in each individual situation.

My only real problem is with what I consider deliberate marketing tactics meant to mislead a purchaser into believing the product is, or can perform, as something it isn't. A clear explanation of just how the unit really works is needed, especially if the company wants to be held blameless for problems caused by misuse.

Great product, would buy from again. Better than advertised as it is weighted and sinks to the bottom of the water.

Buy Hagen Marina Betta Submersible Heater for Aquarium Now

My poor little Betta was freezing in his 1/2 gallon glass bowl. I upgraded to a 1 Gal square tank and added this heater. His water is now just a little cooler than luke warm. He is happy, spunky, and even made his bubble nest the day after I placed him in his new and warmer enviornment. It only took about 4 hours to get his water to a consistant temp and it has remained that way.

UPDATE: 01/28/13

Well, this heater keeps the water at a nice temp for ME but not my Betta. I only have a 1.5 gal environment for my fish so this heater began to make my fish sick and he almost died. I read on a site that a heater should not be used unless my fish is in a 5 gal or larger tank...oops!

I took the heater out just in time to save my beautiful fish. I'm keeping the heater because I will eventually get a larger tank for him.

This product did do its job, so it's nice.

Read Best Reviews of Hagen Marina Betta Submersible Heater for Aquarium Here

Good heater for a small Betta bowl. I had 0.5 G bowl and it works really well for me. Would recommend it to anybody.

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We ordered our first one of these heaters for the betta tank in our kitchen since it seemed to get pretty cold during the winter. It kept the water at a nice high-70 degrees in a 1.5 gallon tank. The betta went from brooding at the bottom to swooshing around the tank, chasing after us as we walked by. He was obviously much happier, so we bought a second heater for the betta in our son's room. Now 'Decepticon' is also much more active as well. We feel bad that the cool water was obviously having a bad effect on the fishes' metabolism, but now that they are warm they will have longer, happier lives.

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