---
product_id: 16221136
title: "Crystal Plex - Lake and Pond Algaecide Treatment - Liquid Copper Algaecide Kills and Prevents Various Types of Algae (Planktonic, Filamentous, Chara) - 1 Gallon Treats up to 1 Acre"
brand: "crystal blue"
price: "1108 kr"
currency: DKK
in_stock: true
reviews_count: 8
category: "Crystal Blue"
url: https://www.desertcart.dk/products/16221136-crystal-plex-lake-and-pond-algaecide-treatment-liquid-copper-algaecide
store_origin: DK
region: Denmark
---

# 1 gallon treats 1 surface acre Kills planktonic, filamentous & chara algae 100% safe for humans, fish & pets (except koi/goldfish/trout) Crystal Plex - Lake and Pond Algaecide Treatment - Liquid Copper Algaecide Kills and Prevents Various Types of Algae (Planktonic, Filamentous, Chara) - 1 Gallon Treats up to 1 Acre

**Brand:** crystal blue
**Price:** 1108 kr
**Availability:** ✅ In Stock

## Summary

> 💦 Clear waters, zero worries — your pond’s new best friend!

## Quick Answers

- **What is this?** Crystal Plex - Lake and Pond Algaecide Treatment - Liquid Copper Algaecide Kills and Prevents Various Types of Algae (Planktonic, Filamentous, Chara) - 1 Gallon Treats up to 1 Acre by crystal blue
- **How much does it cost?** 1108 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.dk](https://www.desertcart.dk/products/16221136-crystal-plex-lake-and-pond-algaecide-treatment-liquid-copper-algaecide)

## Best For

- crystal blue enthusiasts

## Why This Product

- Trusted crystal blue brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Safe & Sound:** Formulated to be 100% safe for humans, pets, fish, and birds—peace of mind included.
- • **Algae Annihilator:** Powerfully eliminates planktonic, filamentous, and chara algae for crystal-clear waters.
- • **Targeted Treatment:** Apply in sections (1/3 to 1/2 pond at a time) for maximum effectiveness and safety.
- • **One Gallon, One Acre:** Efficiently treats up to 1 surface acre, making large pond care effortless.
- • **Season-Long Serenity:** Prevents algae regrowth and swimmers itch, keeping your pond pristine year-round.

## Overview

Crystal Plex is a liquid copper algaecide designed to kill and prevent multiple algae types including planktonic, filamentous, and chara. One gallon treats up to 1 surface acre of water 1-3 feet deep. It’s 100% safe for humans, pets, fish (except koi, goldfish, trout), and birds when used as directed, making it ideal for maintaining beautiful, algae-free ponds year-round.

## Description

desertcart.com : Crystal Plex - Lake and Pond Algaecide Treatment - Liquid Copper Algaecide Kills and Prevents Various Types of Algae (Planktonic, Filamentous, Chara) - 1 Gallon Treats up to 1 Acre : Algaecide Water Treatments : Patio, Lawn & Garden

Review: Tough on Planktonic Algae - We have about a 1/4 acre pond that turned into pea soup as summer dragged on. It was 80% covered with planktonic algae right below the surface of the water. Together with some black dye and this we’ve pretty much knocked out the algae. I used a power sprayer to treat the pond and over the course of 48-72 hours the algae was gone. I’ll treat again in 14 days to keep it at bay. This product worked great for us.
Review: West gloves and don't use if the wind is blowing. - Be very careful around your pond with the vegetarian you want to keep. This product works. It will kill all the bad growth in the pond and on the shore line.

## Features

- Controls many types of algae such as filamentous, chara, planktonic and swimmers itch for a beautiful and safe pond all year long
- When used as directed, Crystal Plex is 100 percent safe for humans, fish, livestock, pets, birds, swimming and irrigation
- Not for use in Koi, Goldfish, or Trout ponds
- Treat only a third to half of your pond at a time
- One gallon treats 1 surface acre 1-3 ft deep

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B000IOBRBY |
| Best Sellers Rank | #23,724 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #42 in Water Garden & Pond Treatment |
| Customer Reviews | 4.0 4.0 out of 5 stars (891) |
| Is Discontinued By Manufacturer | No |
| Item Weight | 9 pounds |
| Item model number | 444 |
| Manufacturer | Crystal Blue |
| Product Dimensions | 6 x 6 x 12 inches |

## Product Details

- **Brand:** Crystal Blue
- **Item Form:** Spray
- **Item Weight:** 9 Pounds
- **Liquid Volume:** 128 Fluid Ounces
- **Manufacturer:** Crystal Blue

## Images

![Crystal Plex - Lake and Pond Algaecide Treatment - Liquid Copper Algaecide Kills and Prevents Various Types of Algae (Planktonic, Filamentous, Chara) - 1 Gallon Treats up to 1 Acre - Image 1](https://m.media-amazon.com/images/I/718k4O+LBeL.jpg)

## Questions & Answers

**Q: Is Crystal Plex safe to use with fish?**
A: This product is safe for livestock, recreation, potable water and not harmful to most fish when used according to label directions. There are a few exceptions, Crystal Plex is not meant for small deco ponds and is toxic to Koi, Goldfish and Trout.

**Q: How often should I use Crystal Plex?**
A: Crystal Plex algae control should be used when algae is present. Wait 14 days between applications and only treat a 1/2 or 1/3 of the pond at a time to recover oxygen levels.

**Q: How do I apply this product?**
A: Apply by mixing and spraying algae.

**Q: How much product do I use?**
A: 13 oz. of Crystal Plex mixed with a couple gallons of water will treat 1,000 square feet.

**Q: When is the best time to treat my pond algae?**
A: Pond algae should be treated when algae is actively growing and water temperatures are above 60F.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Tough on Planktonic Algae
*by G***5 on August 18, 2025*

We have about a 1/4 acre pond that turned into pea soup as summer dragged on. It was 80% covered with planktonic algae right below the surface of the water. Together with some black dye and this we’ve pretty much knocked out the algae. I used a power sprayer to treat the pond and over the course of 48-72 hours the algae was gone. I’ll treat again in 14 days to keep it at bay. This product worked great for us.

### ⭐⭐⭐⭐⭐ West gloves and don't use if the wind is blowing.
*by P***N on October 21, 2025*

Be very careful around your pond with the vegetarian you want to keep. This product works. It will kill all the bad growth in the pond and on the shore line.

### ⭐⭐⭐⭐ Summertime fun on Bickford pond.
*by S***K on August 6, 2025*

I have had great success with both Crystal Plex and Crystal Blue. I am giving only 4 stars because after looking like a successful application of Crystal Plex, two days later I had to apply another gallon dose because the algae reappeared just about immediately. I had also applied a dose two weeks before. I have never had a problem before and have used it successfully for several years. I am hoping this last dose does the trick. I am attributing the reappearance of the algae to the unusual weather this summer. It has been hotter than normal, and except for early spring, we have had no rain. My overall experience with these products has been remarkable. I am certain I will be able to give it 5 stars next time around. The two gallons I just received are for future use. The pond I use it in is a swimming pond for the grand and great grand children( and this year the older adults

## Frequently Bought Together

- Crystal Plex - Lake and Pond Algaecide Treatment - Liquid Copper Algaecide Kills and Prevents Various Types of Algae (Planktonic, Filamentous, Chara) - 1 Gallon Treats up to 1 Acre
- Crystal Blue Natural Pond Cleaner - Muck and Sludge Remover, Safe for Koi - 1 Gallon
- Crystal Blue Lake and Pond Dye - 1 Gallon - Royal Blue Color Treats up to 1 Acre - Clean, Clear & Crystal Blue Water - Environmentally Friendly Pond Dye

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*Product available on Desertcart Denmark*
*Store origin: DK*
*Last updated: 2026-01-26*