FREESEA Aquarium Fish Tank Heater: 25W Small Submeisible Water Heater with Preset Temperature for Betta | Turtle | Saltwater | Freshwater | 1-5 Ga...

Im a relatively new aquarium owner (55 gallon), with the recent temperature drop outside, my tank also got colder. I panicked because this will be my first winter with a tank and my fish need to be @ 73-77 degrees. I ordered this heater about a week ago, and it did not work. More panic. My tank would not warm up. I did the online support through ZeeBooth, which was really helpful, but unfortunately, it was just a bad heater (would come on but wouldnt stay on and do the job). I reported and it and company instantly sent out a new heater, I received it the next day. The new heater does work and it worked VERY fast. Last night (approx 9pm) I put the new heater in, and the tank was @ 70.3 degrees. Wake up this morning (6am) to 73.5 degrees. No more panic for my fish babes. 5 stars because 1) it is a great, fast working heater. 2) the company did what was right and replaced the damaged heater, very quickly. 3) my tank has a pretty reliable temperature gauge, and Im getting the same readings with the separate temperature gauge that came with the heater. All in all, happy with the product, company, and price. My fish are out and about this morning and look much more lively than they did yesterday. Thank you for getting the replacement heater to me so quickly!

Although there are slightly cheaper heaters for sale, these ones adjust to the temperature you want and automatically turn off to prevent overheating unlike cheaper heaters. Both came with high-quality digital thermometers which was a wonderful bonus. They read within 0.5F of each other when placed in the same tank, and having two was nice for acclimating fish to the heated tank so I could be sure that both water temperatures were the same. I ran the first one I set up for 24 hours with no fish to test the temperature (and used a thermometer not included to compare) and the water temperature stayed at or slightly below the temperature I set. If you are deciding between two temperature settings (theyre in increments of 3F I think) I would recommend the higher one because the thermometer will turn off when the set temperature is reached, and the tank will cool a few degrees before it turns back on. Im very impressed with this heater and am glad I bought two. The digital thermometers are a lot more accessible than the ones I had because you can check the temperature with a glance from the other side of the room instead of having to get close to the tank at the right angle and squint to see the mercury inside the other one, and you can move them without getting your hand or whole arm wet. Ill keep them off except to check the temp after a week or so of good use so the battery doesnt run out. It takes a couple hours for them to heat room temperature water to the warmth I wanted so I would recommend starting with warmer water if you dont want to wait. Update: 48 hours later, after putting the second one in my 3 gallon tank, the temp was up at 88F despite being set on 81. Not super concerning, and likely just because this tank is smaller than the other and is near another source of heat (hydroponics heater). I turned the setting down to 77 and added a few ice cubes to speed things up and will update if the temperature stabilizes at the desired temperature (80-84). I have no fish in the tank as I typically dont with new tank devices for 24 hrs. This is partially my fault for keeping such a small tank in an area where the temp fluctuates a bit, but I expected the heater to turn off as a result of the added heat. The temp outside the tank is 76. Update to the update: the temp fluctuation was most likely a result of a semi-rapid increase in room temperature. We usually keep the house at around 68 but when the sun comes in the big SW windows in that room and the door stays shut, the room rises about 10 over a few hours, which must have been enough to raise the tank temps for a bit, especially if the heater had just shut off. I kept the setting lowered on the one heater and have been monitoring the temps and they are clocking in (or thermometering in, if you will) within the desired temperature range.