Cool! I have a german blue ram in my community aquarium with gourami an angel clown loaches and a bala shark and some cherry barbs. The play sand will definitely work for you. They do love poking around in the sand Ive heard as well. If it were me... I would run the filters the silt you are seeing build up will easily pass through your filters and get trapped by your filter pads. I was just reading that you have 2 electric blue jack demseys in with some mollies and black skirts.... I would suggest reading up on the tank mate choices for your dempseys also tank size. 20 gal
is not nearly enough for your some of your fish let alone all of them in the one!