18W Aquarium UV Light for 100-1000 Gallon, UV Pond Water Clarifier for Koi Pond, Swimming Pool, Spa, Large Fish Tank, Cold Plunge UV Light for Pond Algae Control

This light works great! I used it in my 1800-gallon koi pond. This is the first year out of 15 years without one of our large shade trees that helped shade the pond. Excess rain and increased sunlight caused an algae bloom and the water was deep green... so bad you could only see 4 inches deep. I tried algae treatments that worked well in the past but losing that shade tree was just too much sun. Ran this light for 4 days straight and it cleared it right up. Now, clear water 3 feet deep. Unbelievable!

It's working wonderfully. I love the waited and as suction cups never hold very well.. I put it in my 2000 gallon pond. It cleared it up in three days.. I got nervous about seeing how many returns but I don't understand why this light has worked well.

My pond is still green. Checked and the UV light is not on. Checked all connections. Everything is working fine. Very sad. I even tried another plug but still nothing. 28 days.

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

UV light water purification waterfall, works as expected, good build / sturdy housing.

Works Great, I have a natural 30' by 20' by 4' koi fish pond that has had algae growth problems for the last 3yrs. Come summer the water turned dark green. With in 2 to 3 weeks of use it has killed off the extreme algae growth so you can see the bottom the the pond! (I have a extra pump setup to help oxygenate the water in a catch basin away from all the koi fish where I placed the UV light)

Our 100 gallon pond does not stay clear of algae overgrowth despite trying various additives. My husband put this light in the pond in the evening and the next morning our pond was clear. We couldn't believe it! The waterfall still had algae on it but that has cleared up significantly in 2 days despite not having a light directly on it. We are just amazed! I wish I would have taken a picture before we put the light in but here is the next day result. Highly recommend this for ponds. We don't have fish in the pond but my plants look fine. Amazing.

Why did you pick this product vs others?:This is a fairly inexpensive device to clear debris from a pond. I doubted it would work but based upon a few of the reviews I read, I was willing to give it a try. Amazing result! Truly! Our pond went from looking more like a mud puddle to crystal clear in 4 days. Thank you to the gentleman who posted a video showing his pond from day one to day four. We had the same results. I can actually see my fish!!!!