A system for mixing slurry includes a tank to contain the slurry during mixing and one or more scales supporting the tank so that the weight of materials added to the tank during mixing of the slurry can be measured. The system may further include a recirculating pipe coupled to recirculate at least some of the slurry removed from the tank by returning a recirculated slurry to an opening in the top of the tank. A feed pipe is positioned to provide fresh powder to the tank by mixing the powder into the recirculated slurry.