What volume of pool water is needed to generate 1.000 L of Cl2(g) at standard temperature and

Question:

What volume of pool water is needed to generate 1.000 L of Cl2(g) at standard temperature and pressure if the pool contains 4.0 ppm HOCl and the water is slightly acidic? The chemical reaction is as follows:
HOCl(aq) + HCl(aq) ( H2O(ℓ) + Cl2(g)
Assume the pool water has a density of 1.00 g/mL.