Question
How do I get the pink hydrangias to turn blue, I heard some kind of acid?

Answer
Hi Dennis,
Thanx for your question.  Use Miracid (from the Miracle Grow people) or your local nursery or DIY should have some amendments that include aluminum sulfate.  This is what it takes to get blue hydrangeas however, if this is a TRUE pink hydrangea, the amendments probably will not make it turn blue.  Nikko Blue is one of the most well-known blue hydrangeas but will turn pink if the soil is too alkaline.  I hope this helps.
Tom