My 75 gallon aquarium got to 69 degrees after my old heater failed. It only took 2 days to get it to 81. I increased it a few degrees a few times a day. It probably could have gotten him back to 81 a lot quicker, but I didn't want to put my fish in it. The product is well made and easy to use. I will update my review if anything changes. It works great so far.
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