Green Killing Machine

This is a review of the Green Killing Machine UV sterilizer for aquariums.  My planted aquarium had been stable and crystal clear for over one year.  About 3 weeks ago the water became cloudy and then pea-soup green.  Possible factors contributing to the algae bloom were:

• Dead fish
• The CO2 tank ran out possibly giving the algae a competitive advantage over the plants.
• A wiring error in which the LED lights got plugged directly into a power strip, instead of the timer, leaving them on continuously.  This was discovered after completing the treatment of the water with the Green Killing Machine.

Whatever the cause, the tank had a severe algae bloom.  Earlier this year in the summer my pond had an algae bloom and it was successfully treated with a UV sterilizer so I thought I would try the method on this tank.

What It Is

The Green Killing Machine consists of a small powerhead (water pump) and a sealed UV fixture.  A DC power supply connects to a controller.  The controller, in turn, has one wire connecting to the powerhead and another wire connecting to the UV light fixture.  The unit is reasonably small and fits comfortably in my 30-gallon tank.

It comes in different sizes, and I chose the 9-watt model which is rated for tanks up to 50 gallons.

How Well Does It Work?

It took 5 days for the water to completely clear.  After that, I put the Green Killing Machine on a timer to cycle it on 4 hours per day.  The UV light needs to be replaced after 6 to 9 months of continuous use. One can prolong the bulb replacement cycle and powerhead maintenance intervals by only running it part of the day.

Day 5 of treatment.

A nice feature of this unit is the pump and light connect to each other so that you don’t need to plumb it into your existing pump’s water output.  It’s basically “plug-and-play”.  It’s power requirements are minimal.

Green Killing Machine on Amazon 9 watt model   ($45.95 at the time of my purchase)

See my review on Tetrapond UVC-5 Greenfree Ultraviolet Clarifier