A Nitrite & Nitrate Removing Sponge is designed to help reduce harmful levels of nitrates and nitrites in aquarium water, which can be toxic to aquatic life if left unchecked. These sponges work through biological filtration, providing a surface for beneficial bacteria to thrive, which then break down nitrates and nitrites into less harmful substances like nitrogen gas.

Here’s a general overview of what these types of sponges offer:

Features:
1. Nitrate & Nitrite Removal: Reduces toxic nitrate and nitrite levels, improving water quality.
2. Biological Filtration: Provides surface area for beneficial bacteria to break down harmful compounds.
3. Suitable for Freshwater & Marine Aquariums: Ideal for both types of setups.
4. Easy to Use: Fits in most filter systems (canister, HOB, sponge filters).
5. Durable & Low Maintenance: Long-lasting and easy to clean.

These filter sponges typically contain specialized materials or coatings that encourage the growth of denitrifying bacteria, which is responsible for breaking down nitrates and nitrites. Depending on the brand, some may also include extra features like activated carbon or other media to further improve water quality.

For specific models like XINYOU  or other brands, size, material, and application might vary, so checking the product details would provide the most accurate information.