K&H Pet ProductsPond Heater for Small Outdoor Ponds with Fish, Thermo-Pond Perfect Climate Submersible Deicer, Oxygen for Live Fish in Winter, Thermostatically Controlled, Safety Listed - 8in 300W

This underwater guy has been a trooper so far. I put it in when the air temp started hitting 40. I think it kicks in at right about 34 degrees. It keeps a small hole through the ice, about 1.5 inches in diameter when placed about 8-10 inches deep.They say it's safe for pond liners but I don't want to take any chances so I put it on a flat rock.I have goldfish and mosquito fish in my 200 gallon garden pond, the mosquito fish love to hang out just above this heater.I use a floating heater on the other side of my pond, I have already had to replace that once because it sank. The floating heater makes a much bigger hole that my goldfish enjoy, but it's less reliable than this heater.

I was having difficulty keeping my pond temperature at the right level during all the cold weather we were having. I lost several fish and some "sucker" fish that I'd had for awhile in my pond. This pond deicer was highly recommended by The Pond Guy. So I bought it, and I am so happy I did. The pond now remains at the right temperature for my fish. I am so relieved. I'd been so worried and frustrated that I couldn't keep the temperature at the right level. The fish are swimming around as they should be and all is well!!

So far item arrived dead, does not do anything. I put it in the pond that is well under 300 gallons 2 days ahead of a freezing snap while there was no ice in water, plugged it in to give plenty of time for thermostat to read temps are dropping to freezing and turn on yet yesterday pond had a layer of ice on top and no fish were around it which shows it is not doing what it is supposed to do or working at all. I rechecked it was plugged in and outlet was working which they were. Company said to put in freezer to make sure working but that is easier said then done with most freezers and even if it was technically working it is still totally useless, it allowed ice to form all around the pond and did not make a hole anywhere above it nor are fish around it indicating there is no or unacceptably low heat radiating off of it and rising. I emailed and provided the company with pictures of the frozen pond above the de icer in a email and with the reply it seems like they actually want me to pay to send it back to get a functioning one because I saw no pre paid packaging slip and they require me to return it for a refund or replacement so they can inspect it. I checked the small pond this morning and it is just frozen more solid which I again took pictures of and provided to the company, if they require me to pay to send it back I will return it through Amazon for a refund and hopefully not be charged to send back a defective non functioning item.

Seems to work well. As long as it's put in before freezing.

I have this in my little 55 gallon pond in N.E. Pennsylvania. The temperature is around 10 degrees here now. I have my regular set up in there that I do in the summer. I don't have one speck of ice at all.. my pump is flowing fine. I even have tubing routed up and out of the pond and around the back for my little "waterfall". This is my second year using this heater and I am totally satisfied with it. It does make my heater bill go up by about 20-30 bucks though... but I don't care. I don't want to have to worry about my fishy friends. I would buy this heater again. I didn't want a heater that left a "hole in the ice" .. I wanted an ice free pond..and that is what I have. I have your standard drop in small rigid pond liner. My fish are swimming around and enjoying the winter.... I wish I was enjoying it as much. :)

This would probably work fine as a de-icer, but in Houston, my pond never freezes over. I bought this to submerge into a cranny in my pond to give my pleco a place to hang out during a cold snap so they would survive. It didn't work. The water around the heater didn't heat up enough to give them a warm space, and I lost all of them and one was almost a foot long. I'm still looking for a heater for this purpose and have yet to find one.

I bought this item last fall when I had doubts about my old pond deicer. I have a small pond, 7 by 14 feet and 18 inches deep. I run a water pump all year that pumps water up to a bog level about 5 feet above the pond. The top of the pond did ice over in the extreme cold, but the heater kept the water under the ice at a good temperature, and the pump and waterfall ran all winter. I positioned the heater on the bottom next to the water pump. I am quite pleased with the unit. And, the fish hanging around the heater seem quite pleased as well.

This heater was too big for my tiny pond so I had to return it. The cord was really heavy duty so it looked like it would have done a very good job, I was just hoping the disk part would be smaller than it was, as it was difficult to tell in the picture. It is not huge, just too big for my little 40 gallon pond. They accepted it back without any hassle at all. A great experience. If this company would make a smaller disk at about 200 watt instead of 300, it would be perfect.

We purchased 2 of these on July 15th\2018. The first one worked great for a few years. We put the second new one in another pond this winter starting in January\2024 and it hasn't worked at all. The pond is frozen with at least a 2 inches of ice. In fact the heater is frozen into the ice. [ we have had to come up with other means to keep a hole in the ice for the fish since the heater can not be removed.] If we could get a refund we DEFINITELY would.

Simply plug it in / and submerge. I have it on a timer. Cold plunge is always ready to go and not totally frozen. Not the intended use. However another use for it.

I'm using this heater for my 120 gallon pond. Seems to be working great so far. I'm hoping it will keep the frog population alive over the winter as the pond normally freezes solid. I tried relocating them to the only pond in my area deep enough but they returned within 10 days. It's amazing how far they will travel to return "home" It's advertised as being compatible with an air/water supply. I thought that meant there was a provision to hook an airline to it to provide aeration as well. What's actually provided does nothing to assist that whatsoever. It's misleading and shouldn't be included in the advertising. I'll know more about the heater once the deep freeze comes and will update the review accordingly

Priced right and works exactly as advertised

I always had a floating heater but it’s February in Alberta and pumps are still running fine with the submerged one. I did however create a snow igloo over the pond which probably helped. I will check if the fish survived the winter and post another review in spring.