I,ve used 100% perlite for years, it is absolutely inert no ph or e.c efects. Like the chap has said poke some holes in it to rinse the white powder away. A good tip is to make lids for your pots they help keep down the r.h% they stop the perlite drying at the top of the pot which in turn helps prevent/stop salt build up. Also it does wick very well i used it in smart trays, so it was depending on capilary action. It,s quite surprising the amount of water it holds over time, it apears to be a common misconception that it does not hold water, not the case you would get away with a few days not watering a (10/15ltr) pot without any problems. hope this helps TCD