We've put together the best products for your spring pool opening: Algaecide, Shock and StainFree. 

Ultra 40 is a 40% polyquat algaecide while Ultra is a 65% cal-hypo shock.  Add the full bottle of algaecide and 1-2 kg of shock for a standard opening up to 90,000 L (use more shock the greener it is).  StainFree will bring up your pool finish by removing any metal staining that has accumulated.