K&H Pet Products Pond Heater for Outdoor Ponds with Fish, Deluxe Thermo-Pond Perfect Climate Deicer, Winter Oxygen Exchange for Live Fish, Thermostatically Controlled, Safety Listed - 7in 250W

I bought this product in November with the expectation it would just keep a hole in the ice. We had a couple near zero degree nights in Northern Illinois the end of November and it kept the entire Pond liquid so I've kept the pumps running. All through November and December the pond was about 42°. It is now January and we're getting Sub-Zero nights. Last night was 4° below zero and it is still keeping the pond about 34°. My pumps are still running. I tied this thing off so it couldn't float to the edge and melt or burn anything. The only ice I have in the pond this morning is the section where the hornwort grew to the surface of the water. I do think this is a fantastic product and the only downside I would say is being 1500 watts it does consume a lot of electricity. However it does its job and is allowing me to keep the pumps running so I am quite happy with it.

UPDATE 3/21/25 The SECOND heater I bought (see below) has now also failed, after LESS THAN 2 months. I have contacted K&H customer service again, but as of now, I wouldn't recommend this heater to anyone, unless you want to treat it as a "disposable" purchase. I won't buy another one.We'll see what/if K&H responds on this, but I'm not holding my breath, since they didn't respond at all last time.UPDATE 2/24/25 It seems that K&H can/will only respond via AI-generated emails, because I've received NO response from them to my second email regarding the heater not functioning after 2 months. I wound up buying a second heater, as it got quite cold (-15 degrees) while I was waiting for a response from the vendor. So, the following comments apply to the SECOND heater:1) this one has, so far, kept the pond temperature much cooler than the first one - between 42 and 48 degrees F. This is more what I expected from the advertising.2) it got me through the super cold spell, and is currently still working3) I took the heater out of the pond today, and it was already showing significant corrosion, after less than a month of use. I would HIGHLY recommend that K&H apply a coating to the coil, much like is used on AC and heating units. Hopefully, someone from K&H will read this and make the change for future potential customers.4) As I said above, still no response from K&H, which is very disappointing.Overall, the second heater is slightly better than the first one, just because of the lower thermostatic temperature, but I still have to stick with 3 stars, since K&H's customer service seems to be only by bots.ORIGINAL POST:I bought this heater to keep my outdoor pond from freezing my Koi. I started using it in late November and it quit working today (1/29). As others have posted, it just trips the GFI outlet now. I've cleaned the unit (which wasn't that corroded, but to no avail. I live in Nebraska, and it can get quite cold here over the winter.Pros:* it worked well, when it worked. We just survived the deep freeze here that a lot of the country got, and one night was down to -10 degrees. It worked through all of that.* Price is pretty competitive* It DID heat the whole pond (I used it submersed) most of the time, with just a thin layer of ice around the corners of the pond during the extreme cold spellCons:* The advertising led me to believe that it would keep the water "just above freezing", but the unit I got consistently heated the water into the high 40's to mid-50's. I questioned this with K&H, and they said that was "normal". Ok, not a super problem, other than paying for electricity to heat water unnecessarily, AND my fish wanted to eat all the time instead of sleeping.* It doesn't have a thermostat that can be controlled by the user (see above)* It really needs an "in use" indicator light on the unit, so that you can tell when your money is going down the drain for electricity* The unit quit working after 2 months.In retrospect, I probably should have just purchased a deicer, but I was nervous because my pond is only about 18" deep. I have bought another unit, which will hopefully last longer.I would probably have rated this 4 stars if it had continued to work (deduct for the "overheating"), but for now, I'll leave it with 3 stars, and see how the second unit performs.

So far so good. I am new to taking care of Koi fish. I have taken care of large fish inside of a fish tank, but never in a pond. I had a feeling that the temperature outside could potentially harm the fish so after researching proper care of Koi fish, I realized I was in our need of a pond heater.. This heater is working great so far. Outside temperature is 41° and the pond water is steadily rising from 32° to 35.8°. I will check the temperature again with my laser thermometer tonight and see if the temperature maintains or falls and by how much. Delivery was fast! Directions very easy to follow.Update: temps have fallen to 29° outside and the heater is holding around 30° to 33°.

First one MELTED while in the water in WINTER?!?!?

Absolutely great product. It kept my fish pine from freezing over. I’ve had several heaters for my pond. This one is definitely kept it from freezing over the whole pond was actually not frozen other heaters. It would just be a circle around the heater. This was my whole paw it’s a big paw. I have about 30 coins in there. I highly recommend it.

I was worried about reviews but so far this has worked perfectly and since i bought the 1500 watt item I was wondering if it would be enough for my pond that is a 15x15 liner and 30 inches deep. not sure how many gallons exactly but if i just leave the thing on all the time the pond does not have any ice except where it flows down the rocks. this got me wondering how much electricity it uses and i attached it to a plug that i can look at from my smartphone and see how many hours a day it is actually drawing power. I have since started to run it 30 minutes an hour and it keeps the pong half clear and half ice. So hope this helps...i believe the device is able to turn itself on and off to keep the water above freezing temperature but if you lift it out of the water while it is on you will see just how hot this thing gets! it actually can burn off the scale or mineral deposits from the pond by doing this. I like this very much but i am now buying the 750 watt item for my small barrel at my main home (the 1500 watt is running at my second home) so far I can not see any way that this would break and i have been using it for 2 months in denver winter. If it breaks i will update if not i typically do not come back to my reviews. oh by the way do not touch this to see if it is working! :) it is crazy hot even in the water but out of the water it heats up so hot it burns off the scale and you can gently poke the layer off or just dip it in the water a few times and the water will knock the layer right off and it looks like brand new again! I use it floating but it can be used at the bottom if you want by simply unscrewing the top part that has the floating device, you can unscrew it without any tools. I like that. my goldfish likes to hang out around the warm water so i make sure to keep it in the middle away from the raccoons reach :)