FREESEAAquarium Fish Tank Heater: 300 Watt Submersible Betta Heater - Adjustable Thermostat with Thermometer for 40-60 Gallon Marine | Saltwater | Freshwater

I have this heater in an 8.5 gallon tank. Ambient temperature is 68°. The tanks is located on a granite countertop.While the heater works, I can't say that it works too well. For starters, when you get the heater, ignore the temperature dial on the top. It's absolutely useless. If I were to set it to 78°, my tank would be at 85°+. Even after setting the temp to shut off at 78, the temperature swings from 72°-78° which makes me a bit uncomfortable. I don't recommend this if you're keeping fish with sensitive temperature requirements. As it stands, that 6° window is just barely enough for the few guppies, tetras, shrimp, and plants I have. I will likely be setting up a spare thermostat to manage temps more accurately.

After looking at the rip-offs at petco I decided to go online and take a chance for my fish.I've gone through so many of these and this one is great. For the price it's amazing. I have a 10 gallon tank with several fish in it and I like to keep it around 79 to 82 degrees for which this is perfect. I submerged it near the bottom with suction cups and I haven't had any issues so far in several weeks. It stays stuck. The cord appears to be made well.I just had to take one star off because the little temperature gauge that came with it does not work. Maybe it was broken but I really would have liked to have it.

My first nano aquarium had a different model by this company and it did good. Temps varied within a couple degrees, which is stressful to my fish...but it wasn't bad.For my second nano tank, I tried a "name brand" heater from a local chain store. It quit heating completely after three days. I then ordered another "name brand" from Amazon and that one was overheating even though it was the correct size. I finally decided the couple degree variation on this brand was acceptable.It took a few days to dial in the temp. I had to set it lower than what I wanted to get it to hold fairly steady in the 78.5-80°F range. But my tank is now finished it's first cycle and the temps are holding fairly steady. I feel confident this won't stress my fish too much and thank goodness it won't cook him.

Poor quality. Did not work as it supposed toAnd less than a month now , i noticed that sparkles came off of it and almost hurt my fish and it did hurt my snail. As snail climbed up on it, two sparkles shot at it, caused it to fall. And my snail had beautiful antenna, it got damaged from it.Horrible! Im glad i witnessed it and turned off immediately, god i cant and dont want to imagine what could have happened if i didnt notice.Im contacting amazon customer service on this matter and the associate escalated this issue. the team will reach out to me. I am returning this!!!!!Buyer be aware!!!!!!!!!!!!!!!!!!!!!

Easy to install and the temperature readout is a plus. (Do not forget to take the plastic divider out of battery area so it actually works)

Item arrived on time and as expected, but with no instructions. Normally not a problem, but the included digital thermometer didn't work at first, and there were no instructions on how to make it work. I just ened up messing around with it and removing and replacing the same battery a few times and it finally came on. Otherwise seems to be a good heater. I like the temperature settings on the dial.

I made the mistake of picking up a heater from Petco box said it was for a 10 gallon tank, well it was not. I could not get the tank over 66 degrees. I bought this heater because another reviewer had made the same mistake as me. This heater is great! This heater is adjustable, turns off when water hits desired temp. Love this heater, looks good in the tank to. I did not like the thermometer, but that's ok cause I already had a good one of those.

Ordered for my 20 gallon tank and works wonderful. Room I have the tank in gets real cold. After putting the heater in and with in an maybe 2 hours. Temp jumped to where I had it set to. Also comes with a little thermometer that sticks inside the tank. Easy to read what the temp of the water is. Has done very well and would buy again if I need one.