The Cube Gel Block increases filter efficiency and is suitable for use with sand and cartridge pool filters. Increase filter efficiency so your pool stays cleaner and crystal clear. Concentrated clarifying Gel Block binds sub-micron particles including algae. Simple and quick to apply, no mixing, measuring or pouring.
Since D.E. filters are already so effective at removing small particles from the water, Crystal Cubes are not recommended for this filter type.