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

This works great . My tank always had a green color in my water. Now it is crystal clear. What an amazing difference. I love the way my tank looks. I love mine so much I bought my daughter one too. I highly recommend this.

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

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.

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.

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.

It works to remove cloudy greenish tinted algae in the water. Really easy to setup. It takes a few days to get clear water. Just make sure it's not a bacterial bloom. Bought the up to 120 gal one for my 75 gallon tank.

The media could not be loaded. It’s early, but I never thought I had water clarity issues but wow, this really clears out the water column! I bought to kill any potential bad free floating parasites or algae. But the clarity is amazing after just running over night. I have it in a saltwater Waterbox Infinia Frag 125 gal. I placed it in the sump, in my skimmer tank laying down. Only modification, I put a 1/2” hose from the output pump to run directly to my return pump tank. I don’t want to sterilize and put right back in circulation of same tank, I want to sterilize and pump direct back into my return. Hopefully it holds up, I plan to timer cycle it and not run 24/7 and I plan to maintenance clean the pump for longevity

I purchased this item in late October 2023 and hooked it up a few weeks later. It worked amazing in thr beginning. But stopped working 3 months later. The light comes on and that's it.