AA GKM3W Mini Internal UV,Black,AAUV3W-B

Cleared up my 20 gallon tank in 3 days. Had green water. Works great. It was noisy at first but I didnt have the filter locked on correctly.

Easy to setup and install. We’ve had it running 24/7 for a week in our small 10 gallon tank and the difference is obvious. Very impressed so far. We can finally turn on the aquarium light without the water turning green. Hopefully this will last a long time and be easy to maintain.

Returned my first one because the motor was loud and rattling right out of the box. The replacement they shipped me works great and had my tank crystal clear within a week.

The media could not be loaded. I got this GKM for my 10 gallon long tank as well as the next size up (9W) for a larger tank. This 3W sterilizer is barely smaller than the 9 W. I’m actually debating whether I should just get the larger sterilizer even for my 10 gallon.Pros:1) Adjustable flow2) A bit shorter than the 9W version (though really not by much, depending on how you install it) .3) VERY quiet.4) Sponge filter insert seems like it could keep out baby shrimp (though I only just put shrimp in my tank a couple of days ago). You could always but a finer pored sponge, instead. The flow is so powerful that I doubt that it would cause a problem with the function to replace with the finer sponge (remember that SLOWER flow through the filter exposes the problem organisms longer to the UV light, resulting in better effectiveness).5) This is practically “plug and play” in terms of ease of use. The greatest challenge may be finding enough depth in the tank to place it. It’s really convenient not to have to need a canister filter to use this, the way you need to with so many other models.6) No risk of accidentally looking into the UV bulb, which could potentially blind you. This is no exaggeration — I know because I’m an eye doctor.Cons:1) Bulky both vertically and in width.2) You need TWO OUTLETS for this one device. I’m not sure why they didn’t just do the same thing as for the 9W GKM and have both cords connect to a box that then only uses one outlet. 🤷‍♀️ This is annoying and messy, not to mention using up outlets.3) This may or may not be a level 2 UV sterilizer, meaning that it will kill free floating algal blooms, as the name claims, but it may or may not be powerful enough to neutralize (messing up DNA of) bacteria and probably does not kill parasites (such as ich). It’s not clear if these devices have even been tested for the later two purposes.4) Considering that this may be barely above a level 1 UV sterilizer, it’s rather on the pricey side, especially since down the road you will have to replace the bulb and casing, which cost almost as much as the entire machine.5) I get that you don’t have to worry about the casing degrading with UV exposure over time, since you have to replace that whole section at once, but I question how environmentally friendly this approach is. That being said, it is safer than having to handle the UV bulb.

Fantastic unit. I had purchased a competitor's product from Amazon that had no impact on the algae at all. This unit is rated less than half of the UV output of the other model and the algae was gone within 3 days!I highly recommend the Green Killing Machine!

Was working great in our 6 gallon tank, cleared things up within a few days. Had it for about 5 months before it started making a terrible noise and no longer working correctly. Tank started to have more algae again and we’ve had to unplug it. Have seen that there’s a one year warranty but haven’t been able to find out how to access this to receive a refund or exchange.

Had been fighting an algae bloom making my aquarium water opaque green for weeks and NOTHING was working - daily water changes, keeping lights off, minimizing feedings, etc. Have kept an aquarium for the last 10+ years and never encountered such an issue before. This cleared it right up!! It took about 2 weeks of running constantly, but my water is back to being crystal clear. I can't speak to how long it'll last, but it was easy to set up, affordable, and does what it claims to do.

I purchased this for my parents' aquarium and it does clear up the water. It can require a few days, depending on the original condition, but will succeed. I had them originally only have the pump run part of the day to save on bulb life, however, that was unsuccessful. So, let it run continuously, and be sure to, at least occasionally, clean the (sponge-like) filter. Basically, a victory against algae (and more).