Crystal Blue

Crystal Blue Copper Sulfate Algaecide - Granular Aquatic Grade Copper Sulfate for Pond Algae Control - 5 Pounds

$32.99
sizeS

232+ bought in the past month

About this item

  • 99% Copper Sulfate Pentahydrate. To be used for large bodies of water, not small decorative ponds, water features, or pools.
  • Controls most species of algae like filamentous, string algae and swimmers itch. Copper Sulfate should be used as a pond algae treatment on actively growing algae in water temperature above 60F.
  • Most effective when cast out on top of thick floating algae mats. Be aware of how much vegetation you are treating at one time. Eliminating too much at once can deplete the oxygen levels too quickly for your fish.
  • Granular Copper Sulfate, 5 lbs
  • DO NOT use in bodies of water that include Koi, Goldfish, Trout, or Grass Carp. These types of fish are sensitive to copper sulfate products.
$32.99

In Stock

Easy Returns · Return eligibility shown before checkout


How you'll get this item

DeliveryShipping details confirmed at checkout

Fulfillment

Ships fromVentari
Sold by
Bluewater Chemgroup
Returns
Easy ReturnsReturn eligibility shown before checkout
PaymentsPayment details confirmed at checkout

Currently unavailable
Easy Returns · 30-day window
Product details
BrandCrystal Blue
Liquid Volume5 Liters
Item FormGranules
ManufacturerSanco Industries
UPC768980003335
Technical specifications
product_dimensions4 x 4 x 10 inches
item_weight4.93 pounds
manufacturerSanco Industries
item_model_number333
best_sellers_rank#11,832 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #33 in Water Garden & Pond Treatment
is_discontinued_by_manufacturerNo

From the brand

Product detailProduct detailProduct detailProduct detailProduct detail
Product detailProduct detailProduct detailProduct detailProduct detailProduct detailProduct detail

Product videos

Product video 1

Customer reviews

4.42,369 ratings
  1. 575%
  2. 413%
  3. 313%
  4. 20%
  5. 10%

Customers say

Customers find the copper sulfate algaecide effective at preventing and removing algae, making their ponds clear within days.

★★★★★

This is a great product !

mike anspachAugust 3, 2025✓ Verified purchase

I have a 400 gallon pond with a waterfall and I always had an algae issue until I bought this. I know I poured a little too much in but I was thinking "what the heck". The pond was cloudy for a few days and then it cleared the water up and now it looks fantastic! Crystal clear. What a great product ! I would highly recommend this to anyone who has a pond with an algae problem !!! Read more

★★★★★

Does what it says it will do

Christine DaaeNovember 16, 2025✓ Verified purchase

Works very quickly, easy to use. Wear a mask when spreading this! It got rid of a snail and parasite problem within hours! Read more

★★★★★

Copper Sulfate Algaecide

FrodyDecember 2, 2025✓ Verified purchase

Does the job. Distribute through your toilets. Keeps those lines clear of roots as well as the septic itself. Read more

★★★★☆

As advertised

CustomerNovember 28, 2025✓ Verified purchase

As advertised Read more

★★★★★

Lasts a long time and the only thing thatprevents algae in my fountain

MSBJuly 29, 2022✓ Verified purchase

I've tried several different chemical options to treat my ornamental fountain in my backyard, and nothing worked until I used this stuff. Because my fountain is in the full sun, most traditional chemical treatments are ineffective and the algae blooms even when I dose at 2-3x the recommended treatment levels for my application. I had previously tried Tetra Pond Fountain Blocks, EasyCare Fountec Algaecide and Clarifier (worked somewhat in the spring but not the summer) and three of the AquaScape autodosing system treatments (Prevent, Control, Maintain). Not one of them worked, and I would typically have to drain and powerwash my fountain after 3-4 weeks to get a clean, clear fountain again. This stuff is AMAZING! There aren't doing instructions on the label for small areas like my fountain (this amount of chemical is enough to kill all the algae in a 10 acre pond), but you can find it on the internet. For my 500 gallon fountain, I put in 1.5 tsp every other week. I have had ZERO algae growth! This container will last me for many years, so it's not only incredibly effective, it's also really cheap. Everything I've read online would indicate it is safe for animals drinking the water, but it's not safe for fish. Read more

Review image 1
★★★☆☆

Toxic to humans

PatriotOctober 1, 2025✓ Verified purchase

Works with constant application, that being said, very expensive Make sure you don't touch or breath product. Read more

★★★★★

Best value bar none for clearing out the blue-green or black algae in your pool

KJWSeptember 20, 2022✓ Verified purchase

For blue-green or black algae, copper based algaecides are the only thing that work. For other lessor algae foes in your pool like yellow mustard algae, this might not be the product to start with, as it does have some potential downsides. I used this product at 1tablespoon per thousand gallons dissolved in warm water and added it to my pool after balancing pH, total alkalinity, and chlorine levels. After 24 hours, I brushed the pool floor and walls, and rinsed the filter. It was starting to get plugged with dead algae. Then I repeated the brushing and rinsing of the filter after a couple days. The algae was almost gone. Depending on the severity of your algae problem, it may take a few days or more than a week to get it all knocked down. Just remember too much copper in your pool will stain the plaster blue or even grey forever. The dissolved copper doesn’t evaporate or dissipate, so don’t add more than the recommended amounts. Remember, go slow, have patience and don’t overdo it. Does the same thing as the copper based algae killers in the pool store for much less. Read more

★★★★★

It works

kim iretonFebruary 23, 2026✓ Verified purchase

Good Read more

Recently Viewed

We use optional analytics cookies to understand how visitors use Ventari and improve the experience. This banner controls analytics measurement only. See our Cookie Policy.