I have play sand in my frontosa tank and they do just fine. The rinsing is very important though. I remember when I did mine. I put the end of my python in a 5 gallon bucket and poured the play sand around it. Turned the water on to the python on low and left it.........for 10 hours with taking a skewer and stirring the sand a bit around the python. I made sure the end of the python never left the bottom of the bucket which helped to bubble up the particles so they could over flow the edge of the bucket. After doing this with 150 lbs of play sand, I put the sand in the tank. Then I put a plate on top of the sand and directed the the water coming out of the python on to the plate. This kept my cloudiness down considerably. My tank was clear within 8 hours. I have mts in the tank to tunnel through the sand to keep gas pockets from forming in it.