In that case you'll want to take your FC to 20 or higher and do your best to keep it above 20 until you can go from sundown until sunup without losing more than .5ppm FC. Here's the chart and page that explains the calculation: http://poolsolutions.com/gd/best-gue...e-chart.html#a

Also, run your pump/filter 24x7 until you're finished.