Hey it Shawn and iamcanadian lol. Our pool is a public facility with Main Pool 150000 gallons, Leisure Pool at 25000 gallons, two small Hot Tubs and sauna. I recently changed out the sand in Main Pool filter. (broken Lateral) As I put the filter back on line everything seemed good. The next morning the pool was green in color (normally blue). The pool was completely balanced and clear just green. It slowly cleared over 2-3 days back to it original color. Why? What? and can it be avoided next time?