If 0.5 moles of Ca(OCl)2 is completely dissolved in 10L of

ater and this solution is added to a pool of 20,000L of water and mixed together, how would I work out the concentration of hypochlorite ion in the pool?
I would love if I could get the basic working out so I understand the steps I need to take to solve a question like this!
Thank you for your time 🙂