32W Aquarium UV Light for 200-3000 Gallon, UV Pond Water Clarifier for Koi Pond, Swimming Pool, Spa, Large Fish Tank, Cold Plunge UV Light for Pond Algae Control

I had been fighting algae in my Koi pond all Spring and Summer due to a broken inline UV sterilizer. Bought this 18w UV light as a temp fix until a new/larger 55w inline unit could be delivered and installed. Placed this in my waterfall spillway and within a few days the thick pea soup algae was beginning to clear up and was killed off to the point my filters could get the upper hand. Within four days the water was again crystal clear and is now maintaining since I put this in service. Not a difficult install at all. I just placed it in a spot where it would not be visible. This light has performed amazingly at a very reasonable cost. So much so that I am now reconsidering using the 55w inline UV light. Doing an amazing job as advertised. Update: Been in the pond for about three weeks now and all algae has remained under control. One of these is a must have for any pond environment. So much so, that the inline replacement I purchased has not been needed.

The 32W Aquarium UV Light is designed to clarify pond water and improve the overall health of your koi pond. When first installed, this UV light performs admirably, effectively reducing algae and keeping the water clear, which is crucial for the well-being of your fish and plants. Over the course of time the light still remains strong and effective. **3 months later update**

Bought the 18w UV light for my outdoor 125G fish pond. I was amazed how quick it cleared up all the green algae. I put it in the upper portion with the waterfall where the fish cannot go because it stated it can be harmful to fish if put directly in the pond . It is a bit large and did not fit in my filter/pump. I only put in on every few days overnight and it has kept the pond very clear. Prior to this purchase I was using a bunch of chemicals and they did not work too well and I was worried about fish health. I would recommend this product and suggest buying through Amazon as similar lights at PetSmart were way more expensive.

I read some reviews about low product operation stability, yet decided to risk it and purchased 32W version. And it's true: the product itself looks good, well packed, long and thick power cable, but when I turned it on - I had a short circuit right away (probably just in a cord or integrated power inverter). I have a master’s degree in physics engineering and luckily no one was injured: I have a high-quality newest solar system, that I've built myself (Victron) and luckily my 3WA inverter could handle it (cut off the system). It's absolutely NOT acceptable for this kind of submissive device in water. Manufacturers MUST test each model to make sure it works properly. I was planning to use it in my water catchment tank with rainwater, to prevent algae growth (I have a whole-house high-power UV lamp to clean water going through the water pump). I will search for similar and ready to pay 2x price for quality without a electric shock risk. I suggest that the problem might be with place where cable attached to device - it was 180 degrees twisted, this is where the short circuit could happen. I turned it off very quickly and because of my own transformation system it turned the system off, preventing from worse case scenario. Be careful, please. Maybe your will work properly, but be ready for surprises :) Don't put it in water, put of solar glasses and test beforehand. Good luck!

I have been battling suspended algae in my pond for months. I tried everything from Barley packs to natural bacteria to chemical additives, but I was very limited since I have fish, plants and snails in my pond. So most algae additives specifically say don’t add if you have snails. I have a waterfall feature with a filter and it even cleaned out the filter to see if that would help. I was getting nowhere. I eventually decided to try the ultraviolet light because I know one other person that’s in the same situation and his works great. So I decided to put it in an area along the waterfall feature and run it for 24 hours a day. For about the first week, I didn’t see much difference. But after about two weeks, it was crystal clear. I’ve been running this light for the past couple of months and have had no issues or reoccurrence of the algae coming back. I highly recommend this light. My water feature is about 500 gallons and I got the 18W. I think that the light can be changed out because they recommend changing it out every nine months, or every season, since even though the light still shines the effectiveness of the ultraviolet light diminishes after about a year. So I’m hoping that this light has replaceable bulbs since I see Amazon cell replaceable bulbs as a recommendation for this light. I’ve attached two pictures of a before and after, and I’ve also attached a video to show where I placed the light in the water. I placed it specifically in that position because all of the water has to pass through that point and also because it’s highly recommended not to place the light in the same vicinity of the fish and the plants because it’s harmful to them.

one star off just for time of owning, did a terrific job on my 500 gallon pond. Have two other uv s 9 watt that did not keep up with hot weather temperatures. Use in a barrel water fall, so uv light in not in eyes of fish. Does add a nice night glow above barrel at night, lol. Attracks moths to water now. Happy so far.

I have had it since Jul 2024 and it broke June 15 2025 almost one year the glass broke, not sure how, however it was in the skimmer box. Does it clear the water yes, the good news is it completely stopped the whole pond from working to avoid electrical shock, however I also believe it blew the GFI as well so I will need to replace because it won’t reset. I plan on buying another one

I didn't have very high expectations for this product, but was intrigued by some of the before and after photos other users submitted. I had been using a liquid algicide to try and keep the water in our fountain clean, but it didn't seem to do very well unless we started off with fresh water. We also tend to let the pond sit for days at a time without turning it on because the water massively evaporates so quickly out here in dry Colorado. I was stunned to see that after about a week and a half I could actually see far down into the pond, whereas before it was just way too murky. I will experiment with moving the light closer down to the intake of the pump to ensure that it does the best job it can of cleansing the water as it moves through the system. I really don't know how much water our pond holds, so it may not be crystal clear because the lamp is not sufficiently sized. Nonetheless, I was very happy to see the substantial results and would recommend this product without question.