FREESEA Submersible Aquarium Heater for Fish Tanks up to 300 Watts

Dani: I’m 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 Amazon, which was really helpful, but unfortunately, it was just a bad heater (would come on but wouldn’t 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 I’m 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...

United States on Nov 23, 2022

Jackson LJackson L: 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 0.5°F 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 (they’re in increments of 3°F 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. I’m 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...

United States on Feb 19, 2021

AndresAndres: UPDATED: After having this replaced and functioning for a week, I feel I can give a fair review now. I raised from 3 to 4 stars. 5 stars if what the setting I leave it own is consistent. In my 8 gallon, I think it's perfect, however to give it a fair assessment, I thought I'd see where it stabilizes and as it's tweaked for the first 48 hours. The temp I want is 80F. After it stabilized at 78F, I gradually raised it. Mind you, the dial is on almost 90F for it to stop there. Then, gradually I raised it and achieved 80F to 80.5F which made me happy for about 3 days.
Without any changes in the whether, nor lights on in my tank, nor change in the temp inside my house (which is set to 75 now in winter) this thing started jumping up the temp. First I saw it go up to 81 from morning to late night on the 6th day (3 days after reaching the constant 80F I wanted.) I though nothing of it. The next morning it was in the low 82s. It got my attention. By night that day I saw it read 83F and I started to panic. There was nothing I changed, and the tank is clean of algae and all. So why the sudden spike? I don't know. Needless to say I was stuck monitoring it all day as I had to again adjust...

United States on Dec 13, 2020