Is your sand "pool sand." It makes a difference. Try the DE test. (By the way, DE is not sand. You should be able to find it at your pool store.)

Check your manual for how much sand your filter needs. It may be that you are low and need to top it off. The consensus around here seems to be that most people don't think Zeobrite is worth it.

Glad you ordered a K2006. Unfortunately, most pool store testing isn't accurate.