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AA Aquarium Green killing Machine 9W Internal UV for Aquariums up to 50Ga

AA Aquarium
(627)
627 Reviews
|Answered Questions
AA Aquarium Green killing Machine 9W Internal UV for Aquariums up to 50Ga removed from the wishlist
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AA Aquarium Green killing Machine 9W Internal UV for Aquariums up to 50Ga

AA Aquarium
(627)
627 Reviews
|Answered Questions

New Customers: $15 off $49+ with NEWPETCO15

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Description

Please note that the product information displayed is provided by manufacturers, suppliers and other third parties and is not independently verified by Petco.

The GKM9W Internal UV System with Power Head is for aquariums up to 50 gallons.

  • - Helps keep your aquarium water crystal clear & reduce water changes
  • - The GKM9W allows water flow in direct contact with the UV lamp, making it extremely efficient
  • - Fast and easy installation, takes only 5 minutes
  • - All GKM products are manufactured in an EPA Registered Establishment
  • - After assembled approx. dimension 4" x 4" x 12" long. LED signals need for a UV Bulb replacement, easy change without tools
  • - Complete set includes: Water pump, Sealed UV bulb, Control Box, Adaptor. UL listed.

Specifications

SKU1237020
Primary BrandAA Aquarium
Days to ShipShips Next Business Day

Additional Features

Primary ColorBlack
Personalized Item flagNo
SizeStandard

Item Dimensions

Length9 IN
Height7 IN
Width3 IN

Assembly Directions: (1). Connect the pump and the UV Lamp Assembly with the elbow. (2). Submerse the assembly in tank for 30s to allow air bubbles to escape. (3) Submerse the UV lamp assembly and the pump completely in the aquarium and attach to the inside of the aquarium with the included suction cups. (4). Connect to the control box and transformer. Please read instruction booklet inside package. To maximize UV bulb life, we recommend to use GKM when the tank is with green water problem, switch off when water becomes clean or turn it on 8 hours per day.

Reviews

Rating Snapshot

Select a row below to filter reviews.

5 stars

512

4 stars

48

3 stars

14

2 stars

10

1 stars

43

Overall Rating

4.6
422 out of 627 (67%) reviewers recommend this product

Review this Product

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Most Helpful Favorable Review

Makes water Crystal Clear in a week MAX!!!

Aquazan

12 years ago

This product is absolutely exceptional! My aquarium had such hazy/green water th...

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215 PEOPLE FOUND THIS HELPFUL

Show Reviews:

5

and

4

Most Helpful Critical Review

LOVE/HATE

TurtleOwner2

12 years ago

LOVE: It works great. You will see clearer water within a week and it is super e...

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235 PEOPLE FOUND THIS HELPFUL

Show Reviews:

3

2

and

1

Customer Images

Filter Reviews

Rating
1 - 8 of 510 Reviews
Most Recent

117 Ratings-Only Reviews

Does not last

UrbanFarm842

8 days ago
It worked for three weeks and then the unit died. Big waste of money.

No, I do not recommend this product.

Helpful?

Cleared up the green water (floating algae)!

PetFriend7

1 month ago
The 9W Green Killing Machine cleared the water in my 45 gallon aquarium in 7 days! My aquarium has been set up for over 8 years and I always had clear water. In January 2025, I replaced my old (failing) fluorescent light with a new, brighter Fluval LED light. The aquarium looked great, but after several weeks (and 2 cleanings & water changes), the water started turning green. After a few days, I could not view into the tank more than a few inches. This was the first time I experienced an algae bloom. (There were no other changes to my aquarium other than the new light.) I realized I needed to reduce the hours the new LED light was turned on, but still needed to clear the water. Based on a recommendation from my local fish store, I purchased this UV sterilizer (in mid-March 2025). It was fairly easy to set-up. Within a few days, the water started to look clearer. Within one week, the water was crystal clear again.

Yes, I recommend this product.

Helpful?

Great product!

Kels062

1 month ago
I bought this 5 days ago because my aquarium got overran with green algae very quickly. Within 5 days, my water is crystal clear!! I couldn’t be happier with this purchase.

Yes, I recommend this product.

Helpful?

shrimpicide

shromp

1 month ago
This sterilizer does exactly what it is supposed to do. Took a few days to clear up my green and murky tank water. The reason I can only give it 4 stars is because I just watched one of my cherry shrimp swim into the outflow opening, and he came out in chunks about 10 seconds later. If you have curious small animals in your tank, be cautious.

Yes, I recommend this product.

Helpful?

Works well, but short lifespan

MMA3728

2 months ago
It worked great, but for less than 3 months. At this price, I'd expect it to last longer.

No, I do not recommend this product.

Helpful?

Amazing

Desshoe

3 months ago
This thing is amazing. After the first night I could see a big difference, by day 3 my tank is almost completely clear

Yes, I recommend this product.

Helpful?

Great at making water clear.

Japheth16

3 months ago
I bought this a week ago, and it has been the best purchase for my fish tank. It turned green cloudy water to crystal clear.

Yes, I recommend this product.

Helpful?

Down right Garbage with a capital G

OneTrueSancho

4 months ago
The UV lamp died in two weeks of running in the tank. I’m only running it four to six hours a day on a timer. Absolutely not worth anyone’s money. If I got a bad one I’d hate to know what you get. Don’t trust this product. Shop elsewhere and get a slightly more expensive UV sterilizer for your money.

No, I do not recommend this product.

Helpful?
1 - 8 of 510 Reviews

Questions

1 - 10 of 108 Questions
Sort by: Newest Answers
7 months ago

Can this be used in a saltwater tank with corals?

  1. 7 months ago
    The GKM can use in both freshwater & saltwater aquariums. There's no chemical inside the GKM and it helps to clean water by the UVC lamp. Recommend to connect to a timer & operate 8 hours a day, this helps to improve UVC lamp life.



11 months ago

Hello. My tank is very green and I trying to find a way to fix it. But I’m not sure how to when I have baby fish and baby snails.  Would this pump be safe to use with babies in the tank?  I don’t want them to get sucked in. 

  1. 11 months ago
    If you look at the picture, you can see the blue, coarse sponge that goes over the intake. I feel that most babies would not get sucked through this sponge.



1 year ago

What size tubing can fit on this pump and is it outdoor safe? I need something to stop algae growth for my 30 gallon outdoor pond.

    1 year ago

    Is this 9 watt appropriate for my 60 gallon reef tank for dinoflagellates?  With all the rock in my all-in-one tank I probably have closer to 50 gallons in my main display.

    1. 1 year ago
      Hi Max, we will recommend 24W size for over 50 gallons aquarium. In your case, you can still use but may take longer time to see result.



    1 year ago

    Why wont mine come on anymore after I hook everything up again? It had been working fine then one day just would not start again.

    1. 1 year ago
      It may be that the bulb needs replacing from what the info that came with my package says.  The replacement is sold as the bulb in the sealed bulb housing, you can’t open it and just replace the bulb. Hope that helps.



    2 years ago

    I love this product. It cleared my 40 to 50 gallon tank in two days. How do I maintain it?

    1. 2 years ago
      Clean it every 3 months or so, and change and clean the little sponge filter.



    3 years ago

    Can this be used outdoors will be occasionally exposed to rain?

    1. 3 years ago
      This is not the right product for outdoors.



    3 years ago

    I've been having an issue with stubborn brown algae in my 15 gal tank. And now I see some brown algae spots starting to appear in my 9 gal. Would this product help with brown algae (Diatoms)?

    1. 3 years ago
      This product kills bacteria and algae by exposing the water to UV light. A small pump pushes the water through the UV light housing, so you or the fish are NEVER exposed to the UV light itself. My 50 gallon tank sits outdoors, so you can imagine the Algae growth. While this unit does not stop 100% of the algae growth, there is no question that it slows it down substantially (instead of changing water every week, I can do it every 3 weeks...)



    3 years ago

    Can this be used in a 10 gallon tank?

    1. 3 years ago
      Yes it can over power is perfectly fine. You'll get faster results



    3 years ago

    Will this unit help me kill the black algae in my tank? It's been a minor issue but I know if I don't do something it will become a big one and I cannot use algacide in this tank. Fresh water 20g thank you.

    1. 3 years ago
      No, it is primarily a sterilizer. It might reduce the amount of black algae, however.



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