Water Blocks are a great time release algaecide which will keep your pond looking beautiful. Do not use with oxygenating grasses or hyacinths. Totally safe for koi and goldfish. Use full dosage with fish and bog type plants. Use half a dosage if you have water lilies or other sensitive aquatic plants.
This is one of our most popular products.
****Discount for ordering 25 or more is $6.29 per Water Block****