Hi Maureen and welcome to the Disney Parks Moms Panel.
When adding the Water Park Fun & More Option to a 1-Day Ticket for the Magic Kingdom Park, it actually gives you 2 visits to select Walt Disney World destinations, including the 2 Disney Water Parks.
So, as an example, you could visit the Magic Kingdom Park for 1 day, Disney's Typhoon Lagoon Water Park for 1 day and Disney's Blizzard Beach Water Park for 1 day (assuming that both Water Parks are open during your visit).
Tickets and any options purchased must be used within 14 days of first use on both 1-Day Tickets and Multi-Day Tickets.
Currently,1-Day Peak, Regular and Value Tickets must be used by December 31, 2017, but the amount paid for an unused, expired ticket may be applied towards the purchase of a new ticket at the current price, so long as the new ticket purchase price is equal to or greater than the amount paid for the original ticket.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma