Sodium Alginate (seaweed extract) is a gelling agent derived from natural seaweed. It is used to thicken reactive dyes so they can be brushed on fabric like paint. You can mix 1-2 teaspoons sodium alginate granules with 4 cups plain warm water (not hot) + 1/4 cup urea. If your tap water is not soft, add a water softener. Slowly add sodium alginate while whisking continually until fully mixed. Let sit for 15 minutes to 2 hours then stir again. You can store the mixture in wide mouth plastic or glass jars with lids for several weeks. A liquid dye solution can be stirred into a small amount of sodium alginate mixture until it reaches the right thickness. If consistency is too thick, add water to thin. Dye can then be used on garments or fabric that has been prepared with a soda ash soak. Sodium Alginate - Bold Detail is a high viscosity, low solids thickener for all dyes, but is primarily used for cotton. It may be used for silk when fine line definition is not required.