AA GKM24W Internal UV for Aquariums up to 120Ga,Black

Before I purchased the Green Killing Machine I purchased fluval's in-line sterilizer. When using that product I had an outbreak of flukes, which I fought for months. I had to do a major filter tear down on my sixty gallon display tank.But thankfully, that forced me to do more research on uv sterilizers. Apparently most don't cut it, especially for parasite control. Live Aquaria has a great uv sterilizer chart that goes over flow rates and wattages that are most appropriate for your tank. (I included a screenshot of their chart, but the information is also worth a read)This particular model meets my requirements. It's flow doesn't exceed 150gph and it's wattage is high enough to control parasite populations in my tank.The only bummer about the unit at all is that it's large. And it has two ballast boxes. But in a way, that gives me confidence in the unit. Definitely a no bs system. And technically I could have gone with a smaller model (I have a sixty gallon and could probably have used the smaller model) but in the case of uv sterilizers, bigger is better.Installation is straightforward. I don't recommend turning it on and off rapidly -- when you turn it on leave it on for at least a few minutes before turning it off and vise versa (that goes for all advanced lighting systems and will help prevent a blown blub).All in all, I'm grateful that this company is producing an affordable uv sterilizer that's actually robust enough to kill algae and parasites. And I really appreciate not having to touch bulbs ever again.

This worked as advertised . I had a terrible algae bloom that wouldnt stay checked repeatedly returned after several attempts , water changes and algae killer etc etc . I read of this machine and the science behind how it worked in changing the DNA of the algae with UV light in its chamber. As you can see in the before and after shots 10 days apart the system worked and is even clearer today, It also helps to kill bad bacteria in your water . After I’m totally satisfied the algae cycle is broken I will put it on a timer as recommended , as it doesn’t have to run continuously after the algae is gone. The water flow is slow on the unit by design to expose the water to the light longer to do its job , and i can say it surely works

We WERE so pleased with this product and WOULD have gladly given it 5 stars; however, it simply stopped working after merely 6 weeks (actually 40 days)! We read the troubleshooting guide and tried everything from restarting to checking all connections, etc. to no avail. What a pity! This product really works well -- WHEN the UV light is on. Now, we are extremely frustrated!Our tank is 125 gallons and although it took about 2 weeks, the "Green Killing Machine" destroyed the algal bloom exactly as promised, leaving our tank crystal clear. Our fish looked great, the tank was ultra clear and we remarked that we wish we would have purchased one years ago.This all changed, however, when we noticed that the tank was getting a bit cloudy after only 5 1/2 weeks. Figuring it was just temporary, we did not stress over it. Unfortunately, however, it only got cloudier -- and greener -- with each growing day. Troubleshooting simply revealed that the UV light stopped working. Period.Will be glad to update this post and give it 5 stars if the manufacturer/seller makes the situation "right" by fixing or replacing. However, right now we CANNOT recommend this product due to its UNRELIABILITY. What a shame.

I have a 55 gallon freshwater fish tank that just wouldn't clear up from a bacterial bloom, I let the tank try to cycle itself as I have never liked using chemicals to do what mother nature does on its own. But after 2 weeks of waiting for that to happen, I got impatient and decided to try a UV filter, and due to the severity of the bacterial bloom I went with the 24watt in hopes of it clearing the tank up faster, as you can see from picture (1) to (4), those are taken every day until it cleared. This UV filter I know will work as stated on larger tanks but may take a few more days to complete the process. As I can afford too, I will be adding these to my many tanks as I go along.

Another update - It turned out that the problem was not the bulb so the company replaced the whole thing and its been working well ever since. The company has great customer service and is here in the U.S.IUpdate- I contacted the company and they said the bulb was likely defective and are sending me a new one. So I'm going from 1 star to 3 stars. If it lasts a few months I'll bump it up to 4.I ignored the bad reviews and bought it anyway. Don't waste your money. It worked well but the light stopped working after a few days use. I'd turned it off for a few days to put it on a timer and the light wasn't working when I turned it back on. For some reason I thought it came with a second bulb, so i wasn't in a hurry to replace it. It doesn't and it's too late for me to return it.

I ordered this to treat a bacteria bloom in my 69 gallon reef tank. The water was very cloudy (milky white). I installed it as soon as it arrived in the evening and by morning time the tank was visually clearer with some haziness. By the third day the water was crystal clear and the bacteria bloom was fully cured. I have since turned it off and the water has remained clear since. Highly recommend for bacterial blooms that likely won’t go away on their own or do so over a long time and put your fish’s health in jeopardy

First received a used and incomplete item. Sent back and reordered. Got a new one. Took about a week to clear up tank. Now, per manufactures suggestion, I just run it on the weekend. It is maintaining the tank.