Review: Green Killing Machine Internal UV Sterilizer with Power Head

Green Killing Machine Internal UV Sterilizer and Power Head
After 13 days with Green Killing Machine
User Rating: 3.05 (20 votes)

Discover the Green Killing Machine Internal UV Sterilizer with Power Head. Make your fish tank water clear again. A Hidden Gem or Scam?

Why is your tank water cloudy/green/not clear?

Simple: Algae and Bacteria Blooms, the result of excess waste and nutrients in your tank.

The Green Killing Machine 9 Watt UV Sterilizer was designed to turn your water crystal clear again. Lets find out if it really is a “Killing Machine”.

Need to know:

The Green Killing Machine is a submersible combination UV Sterilizer and power head. In theory UV radiation acts as a sterilizer by attacking and destroying the nucleic acids and DNA in algae and bacteria. With the DNA destroyed the nuisance algae and bacteria can no longer reproduce and eventually die off, hopefully making your tank water clear. The Green Killing Machine was designed to utilize this sterilizing nature of UV light to your benefit. Using its combination power head and UV bulb, the Green Killing Machine sucks up the green algae dense water, runs it through the UV bulb and pushes the sterile and algae free water back into the tank.


I have spent over two weeks with the Green Killing Machine (9 Watt version) in my 40 gallon planted tank. Check out my results below:

Day 0

Before- As you can see in the picture above, I have allowed my tank to reach an insane level of algae.

I had been struggling with an unsightly bacterial or algal bloom for a little over a month at this time. I tried water clarifiers, large water changes and even black outs. Nothing had worked, and the water always stayed a foggy mess.

I had heard about UV sterilizers through my research for a solution. However, I was determined not to put any more plumbing and tubing into my tank. I wanted to keep my aquascape as minimalistic as possible and putting a large pump and filter would do nothing for it aesthetically. I quickly realized however, that having a cloudy tank wasn’t aesthetically pleasing either and I decided to pick up the Green Killing Machine UV sterilizer and give it a try.


Retail Packaging

Unboxing- The 9 watt sterilizer filters up to 50 gallons of water, suitable for my 40 gallon breeder. For larger applications see the Green Killing Machine Internal 24 Watts UV Sterilizer with Power Head


The item came packaged well and with an excellent instruction sheet. Setting it up took me just 5 minutes.


Day 0

Profile Shot of the tank – here you can see the installed Sterilizer and the extent of the algae.


The Green Machine Internal UV Sterilizer with Power Head- Installed

Immediately after installation I performed a 50% water change with the 25 Foot – Python No Spill Clean and Fill Aquarium Maintenance System. See that item reviewed here. Logically it made sense to me to do a large water change before running the Green Killing Machine. I wanted to remove as much of the algae and bacteria as possible, making the Green Killing Machines job as easy as possible.

Day 1 Day 1- Landscape Shot (After 50% Water Change)

Day 1

Day 1- Profile Shot (After 50% Water Change)

Day 2

Day 2


Day 4

Day 4

Day 6

Day 6

Day 9


Day 13

Day 13


As you can see The Green Killing Machine Internal 9 Watt UV Sterilizer with Power Head had turned my water crystal clear in just under two weeks.  All it took was a few dollars, a water change and some patience and I was back to a beautiful pristine aquascape.


Green Killing Machine Internal 9 Watt UV Sterilizer with Power Head


  • Inexpensive
  • Really does make your water crystal clear


  • Not pretty. At all.
  • Too big, taking up way to much space even in my 40 gallon breeder



The Green Killing Machine really does work as advertised and I’m shocked because of it. This is the first product in a long time where I’ve thought that I was underpaying for something. However, that doesn’t mean the product is perfect. This is a large piece of equipment and if you can live with it in your tank for a week or two while it does its magic then it’s for you.  At the end of the day, I’m shocked I wasn’t spending more money. This is a hidden gem that more people need to know about.



  • UV sterilizers work by destroying the DNA in algae and Bacteria
  • Might be too big and ugly for some people
  • After 13 Days I had crystal clear water again
  • Keeps fish healthy and happy


Review: Green Killing Machine Internal UV Sterilizer with Power Head
Green Killing Machine Internal 9 Watt UV Sterilizer with Power Head


Review: Green Killing Machine Internal UV Sterilizer with Power Head
August 26, 2014
Simply put: The Green Killing Machine works as advertised!
9.1 Review Score

Simply put: The Green Killing Machine works as advertised!

Build Quality
User Rating: 3.05 (20 votes)

Hi I'm Ryan, the owner of Aquathusiast. I've been keeping fish and aquatic plants for several years now. Along the way I've learned a lot. My goal is to take that knowledge and experience and help you, my readers, create the best aquariums and aquascapes possible. Drop us a line at or join us in the forums for a free aquarium consultation.
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