Pharyngoconjunctival_fever?

I have 4 children they all have gotten Pharyngoconjunctival_fever, My son age 3 is the last to get it, Not positive were they got it but it seems to spread fast throughout the family, My sisters family and a few other families have gotten it. Can you tell me if they can get it again, or if I have to do something to our swimming pool because they have all been swimming in it. My sister also has a pool. Is there anything that can help. We just recently put our pool up could the chemicals in the pool have caused this. Please help Im 21 weeks pregnant and they all have been sick I don't want to do this again its not your typical virus it last a little over 5 days. 4 kids that's a long time. I feel so bad for them and just want to help them. Really cant afford a bigger water bill but I don't want them to continue getting the virus. Have done studying but cant find these answers please help. My oldest age 9 started it it started in one eye they thought it was pink eye, fever and sore throat with it, spread to other eye, first eye was worse than it just spread from there.