Can anyone tell me how many egg whites I can use instead of Meringue powder? My recipe calls for 3TBS of powder.

According to ochef.com, two tablespoons of meringue powder and two tablespoons of water equals one egg white. I used this substitution in a recipe for gumpaste once (I was going the other way, from egg whites to meringue powder) and it seemed to me that it should have been more like 1 tablespoon of meringue powder plus one tablespoon of water to one egg white. The only problem with egg whites is that they can cause food poisoning if they're left out too long, and meringue powder is easy to come by (Michael's and any cake-decorating store).