At first, we should know that 10% means the PAC liquid AL2O3 content is 10%.For Solid PAC powder,the AL2O3 content is around 30%. So the ratio for PAC powder :water= 1:2. For example, 100 gram PAC 30% powder in 200 gram water. The AL2O3 content is 30gram,total solution is 300gram. We got the PAC 10% solution.