If you don't have ro water, then get what ever kind of freshwater you have (tap or well), and put it in a container deep enough to submerse the coral. Get it as close to the temp. of you tank as possible. Put coral in and go look in you fridge and count how many gallons of milk you have, then go look out your front window. Dip is done. You could run your water through some carbon if you think it might help, but if you trust your water enough to drink on a daily basis, then a minute of dip isn't going to hurt anything (I hope). That's how I do mine and no problems. Although I do swish the coral around a couple of times in the dip.