I bought 3 bottles of PH up for my swimming pool in the spring. Two of them were yellowish powder. I found out they WERE the mixture of PH-up powder and dirt after I pulled into the pool because my pool became dusty and there were lots of dirt on the bottom of the pool. The water PH didn't change much. The 3rd bottle was all white powder, and did change my pool PH. Also all the bottles were half full. I went a different Meijer last weekend. I checked there PH up, and found out that all of those bottles were 3/4 full, and all white powder. I believe someone worked on the pool powder IN THIS STORE, and took real powder, and replaced with mixture of the dirt, and also made bottles half full. So DON'T BUY POOL CHEMICALS FROM THIS STORE!