Bioguard Sparkle Up - anyone ever try it in a sand filter? Is it worth the money ...........about $27 bucks for 1.5 lbs. Instructions says it would take about 4 cups for my size filter, so maybe get about 2.5 servings out of a container. I've used DE in the past but you need to be very careful .........this product says that it does not contain any DE. I was going to give it a try this season and was curious to know if anyone has had any experience with it in a sand filter application?