Many people will tell you that you cannot. However, I have used play sand successfully in a planted community tank for many years. There are a several sites that explain the use of play sand if you search for a bit. However, I am unfamiliar with the substrate requirements of Cichlids, which may not get along as well with the sand as the fish I keep, so I would do some research. Home Depot also has large bags of river rocks with can work very well for substrate as well- a little tip, that works at Lowe's at least: bags that are torn open are sold as damaged for half off! I got small $20 bags of river rocks for $10 each, and 2 bags plus a bag of play sand was plenty for my 55 gallon tank!