Safer Sand Komodo CaCo3 sand is a clean, safe and eye-catching substrate. It made from 100% calcium carbonate and has been developed to be digestible if swallowed, helping to reduce the risk of gut impaction. It easy to spot clean and available in a dazzling array of naturalistic and vibrant designer colours. Top tip for tortoise keepers: Use only naturalistic colours when using CaCo3 sand, as bright colours can be mistaken as food.