Actually the hardware store sand was recommended to me by the saleslady who was selling only Zeobrite. She said if you want sand go to a Hardware Store and get silica sand and ask for 20, I guess that is a grade? I know I was not 100% on that either, when you only supposedly change it every 5 years? Even every few years is better than it has been with the Baq., we were having to do every year the last few years. Man, I have to find the posts on Baq and share my 14 years of experiences!! What a crock of horse manure! LOL Isn't that Dutch talk? Maybe I should say, Pool Store manure, LOL!