Tetra Algae Control Pond Block Water Treatment

By Tetra
Rated 3.9524 out of 5 stars
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$10.09Chewy Price
$9.59Autoship Price
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About This Item

  • For containerized ponds only
  • Limited to use for backyard or homeowner ponds and water fountains
  • EPA approved
  • Not for use with live plants
  • Safe for fish but not for use in non-ornamental ponds
Play Video: Learn More About Tetra From Our Team of Experts
Learn More About Tetra From Our Team of Experts

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Fish TypeKoi & Pond FishKoi & Pond FishKoi & Pond FishKoi & Pond FishBetta
Aquarium TypePondPondPondPondFreshwater
Top IngredientsBarley Straw

Questions & Answers

11 Customer Questions

Is this product safe for dogs? My dogs drink from the pond
Answer by ChewySep 11, 2019
This product has not been tested on dogs but it's recommended that it's diluted into the pond first. Please allow the product to mix within the pond for a few hours prior to allowing the dog near the pond area again

how often do you need to use pond block :
Answer by ChewyApr 12, 2018
For regular maintenance, replace block when fully dissolved (usually after 30 days).

Is the block treatment for algae safe for gold fish?
Answer by ChewyJun 18, 2017
This product is safe for fish but not for use in non-ornamental ponds. The Pond Block is limited for use in backyard/homeowner ponds and water fountains (containerized ponds only). It also is not recommended for use with live plants. That being said, this particular product isn't recommended for aquariums, but Tetra does make items geared specifically towards that.

My ducks swim in this pond, is it safe for them?
Answer by ChewyJul 29, 2021
Tetra has not researched the use of this product with ducks but would not recommend it. They could pull it up and swallow it. We would recommend filtering the water or using something like a barley pillow (after checking with your veterinarian to make sure barley is safe for ducks).

ReviewsWrite a Review

Rated 3.9524 out of 5 stars
21 Reviews
Would recommend to a friend

21 Customer Reviews

Rated 5 out of 5 stars
By Anita on May 17, 2022

Tetra algae control block

I have a 400 gallon water trough that I put two koi fish in until we have koi pond built. I would turn green in a week but I cleaned it out and started again been almost a month still clear. Almost time to put in a couple more blocks. I will continue to use this.

Rated 1 out of 5 stars
By NOPE on Oct 15, 2021

Does not work!

This is my second bad review for a tetra pond product. Not only did my pond filtration kit not work even a litte after two months. But the pond block does not work either! After two months I still have alga and the block is the exact same size as it was when I placed it in. It looked like a concrete block before putting it in and it still does. So spend a litte more money on a better product. Tetra has some great products on the market and I give props where they are do but I will also tell you if your messing up!

Rated 5 out of 5 stars
By JoeS on Jul 16, 2021

Pond So Clear!

After three 90 degree days our 500 gallon fish pond greened up; we could not see the bottom or our fish. Local pond stores recommended products costing 5 times the cost of Pond Block & would take 30 days to work. I ordered from Chewy & had delivery in less than 24 hours. Using just two blocks to start, water was absolutely clear in 4 days. I immediately placed another order & that also arrived in less than a day. I highly recommend Chewy & the Pond Block Product.

Rated 2 out of 5 stars
By dfarr on Sep 11, 2021

Algae control - not

This may be a fine product, but it does (and did) not control algae in our small pond.

Rated 2 out of 5 stars
By Fran on Jun 19, 2021

not working for my bird bath

used a full cube of this substance and even after a week, it has not made any difference in the algae in the water

Rated 5 out of 5 stars
By guearyt on Dec 11, 2020

Amazing Pond Block

Pond Block is now a must for my Koi pond. I have tried numerous chemicals and natural solutions. They worked very little or none at all. In one day Pond Block had my pond water clear. The liner algae is continuously going away.

Rated 5 out of 5 stars
By shatt09 on May 8, 2020

absolutely the best for my turtle/Goldie pond

Hands down the best algae and sludge and cloudy water cure I have ever used in 12+ years. I have don’t the liquid pour in, the rock salt in the filter, vacuuming daily, you name it-we’ve used it. I got these on a whim and thank god, they have been a game changer. My pond gets full full hot sun all day and turns to pea soup quickly. Sure I get huge goldies from the algae but I look to see what my pond looks like rather than a dark green sludge farm. I have only used 6 tablets in my 400gal pond so far and absolutely loving them. So easy so simple and they work. I can’t rave enough about them. Until your have a large red ear slider, 12+ large goodies and live feeding you have no idea the work involved in keeping a pond looking somewhat ok. Now my pond is crystal clear, the rocks inside aren’t even covered in algae anymore. Like I said hands down game changer and now a customer for ever.

Rated 1 out of 5 stars
By FormerCustomer on Apr 2, 2020

Poor packaging

The package was not properly packaged and arrived two weeks after the order. Although the box was undamaged, the lid of the jar inside was broken into three pieces and all the contents were scattered inside the box

Rated 1 out of 5 stars
By Shellycool on Jul 2, 2020

Don’t waste your money!

No difference between before and after use of this product in my pond!

Rated 5 out of 5 stars
By Racegirl on Nov 22, 2019

Helps control

Been buying it for years, always had fountains in the houses I lived in and when the weather gets warm the algae gets bad. It really helps