Minus one.
By now, your tank should be on its way to being cycled and the scrubbies should be in full swing. Start replacing them with live rock rubble or dry rock. Replace them a little at a time. You can get dead rock from Bulk Reef Supply. Texas Holy Rock will work too. Same with raw Travertine if it is pourous enough or Florida Field Stone.
The problem with scrubbies or Bio-Balls is that nitrates are the end product; you'll accumulate nitrates like it was a freshwater tank. With live rock, the nitrates will be consumed and converted to nitrogen (which will gas off). That means you can go longer between water changes and you'll save tons of money.
This would be a good time to look into an ATS too.
