As most instructions may let you believe never position the heater vertically and towards the top but horizontally and at the bottom of your tank. This is because, all advanced submersible heaters including the HT10 work with a thermostat. Most thermostats I've seen so far come in a tubular shape. For such heaters, the thermostat unit is located on the opposite side of the tube as far away from the heater as possible. the problem why most of these heaters appear not to work and being labelled worthless is that they are positioned vertically by the user in aquariums and towards the surface. The problem with this position is that the water heated by the heater at the bottom rises to the top making the thermostat 'think' it reached optimal temperature. This problem is more apparent in aquariums that have no mechanical filters to circulate the water. Companies who develop these heaters test them in a typical environment where adequate water circulation evenly distributes the heated water in the tank causing the temperature to rise evenly and the thermostat to properly shut off the unit when the optimal temperature is reached.
If you position this heater horizontally and at the bottom of your tank this heater delivers.
I have had 5 of these heaters now-I don't live near a pet store and this is pretty much what the local Walmart sells-so I went through a period of accumulating several of them for smaller tanks. I was actually going to buy one from Amazon awhile back because they were less expensive here, but read the reviews and decided to move my fish to larger tanks and buy Aqueon instead. Of the five heaters, all have been thrown out.
Also-let me clearly state that ALL of the heaters were positioned horizonatally in the bottom half of the tank (because I know I will forget to unplug them when changing water, so I wanted them below the level the water will fall to during water changes)-I mention this because someone felt that problems exist when they are put vertically at the top-I've never had them there.
First one-Light still worked, heating did not. Tank temp in Wisconsin winter fell to 62 degrees over night. Tested the heater in 5 gal. bucket of water. Dead, Heater tossed out. Luckily, only lost one fish.
Second one-Water somehow got into heater and electrocuted the fish. Fish and Heater tossed out.-
Third one-Malfunctioned and heated a ten gallon tank to 94 degrees. Somehow the resident (An American Flag fish) survived and is still living today. Heater tossed out.
Fourth One-Malfunctioned and heated tank to 82 degrees-Notice how I caught it much earlier because I got very careful with these heaters!-Tested the heater in a five gallon bucket filled with 90 degree water-then poured additional boiling water into the bucket-continued to heat. Heater tossed out.
Fifth one-Malfunctioned and heated tank to 80 degrees-Again-WAY MORE CAREFUL now-Tested in bucketsame as the fourth one. Heater Tossed out.
It took only TWO YEARS from buying the first heater, for all five heaters being thrown out and replaced with Aqueon. (All five heaters were bought before the first one malfunctioned, btw-or I wouldn't have bought them) Since they were all the same, I'm not sure how long each lasted, but I'd say a good guess is that they have a year of proper functioning in my experience.
If you are using this heater-PLEASE make sure that you never put your hand in the tank with it plugged in, and that you have a very good reliable thermometer on your tank that you check regularly. (I will say, however, a neighbor of mine had this heater in his tank-it took four years before his malfunctioned. Ironically, his was hung vertically at the top of the tank.)
My husband and I have had aquariums for over 20 years (taking about a 3 year break when we were traveling a lot for work) and I've never had a product that seemed to consistenly fail like this. My best advice is-buy the biggest tank you can afford (you'll have less problems and work, believe me)-and then buy any other heater but this one (which would be too small if you have a decent size tank, anyway!) A clue on what kind of performance you can count on is to LOOK AT THE WARRANTY of the product. Some heaters have a lifetime warranty! I only had one box from these heaters still laying around, but the warranty is for ONE YEAR. This should be your red flag. Generally, I have nothing against Tetra or their products-but this particular style heater (and I can't speak on their other designs, I have no experience with them-so read those reviews seperately from this one) is problematic, and I urge you to look at other styles.
Buy Terta Fish Tank Submersible 2-10 Gallon Aquarium Heater Now
I purchased this heater through Walmart 2xs. The first one lasted two days. The second one lasted one day. The directions say "submerge in water, then plug in." That's what I did. The box and directions both say that the heater will maintain the tank temperture at 78 degrees. The first heater I had brought the water temp to 74 and the second made it to 70. Now my fish are cold once again.
On the plus side, I really like the overall appearance of this heater. It is small and blends into the background (that would be why I purchased it the second time).
If you buy this item, I hope you have better luck! (Oh, my tank is 10 gallons. So, if you have a smaller tank, maybe it will work better.)
Read Best Reviews of Terta Fish Tank Submersible 2-10 Gallon Aquarium Heater Here
I have been using this product for several years. I have 4 tanks at differant levels and are all heavily planted. I put this product in weekly. I am constantly giving offsprings away because of their growth and lushness. This product is a must for anone wanting to have live plants. Substrate is critical for good growth.
