Don't know what is in Target Shock and Swim, but I would bet that it is probably costly. At any rate, you don't have to have it. Most people just start there conversion with dumping bleach in and then they are on their way. Be prepared. It will turn all kinds of lovely shades of green along the way, but you'll get there. The more often you dose it with bleach, the faster your conversion will go. Read through the other threads in this forum about other people's experiences with their conversions. Good luck. You'll be glad you switched!