Aquascape Pond Sludge Remover Packs eliminate pond sludge on rocks, gravel, and filtration. Sludge builup is caused by fish waste, plant matter, and other decaying material. The easy-to-use water soluble packs dose the sludge directly and make it easy to spot-treat and treat hard to reach areas. Pond Sludge Remover Packs are safe for fish, plants, and animals. Aquascape is passionate about the products we produce, providing unique products, designs, and features that stand above the competition.