Filter media is used to filter and clean portable water filters and pool filters and sewage treatment plants. It is a highly effective filter media as it hold back precipitates containing impurities. Filter sand size, angularity and hardness are the important filter media sand characteristics to ensure proper filtering.Core sands, gravels, and pebbles are types of materials commonly used in construction, landscaping, and various industrial applications. Core sands are fine-grained materials typically used in foundry applications for making molds and cores for metal casting. These sands are specially formulated to have good flowability, compaction, and permeability properties to allow molten metal to flow into intricate mold cavities and channels. Core sands may be composed of silica sand, zircon sand, chromite sand, or other types of sand mixed with binders and additives to improve strength and dimensional stability.