The play sand doesn't do a thing to the filter motors. I use it in all of my planted tanks. The fish love it and much more natural. I've encountered absolutely no problems using it other than when first putting it in and having to let the tank clear up or doing several water changes to remove the silt. The Stuff looks much better than anything else. As far as buffering, just use baking soda for your buffer, its a safe way to increase your water hardness for the africans, and or add some coral pieces to your rift lake setup. Malawiis aren't as picky about their water pH as the Tangyanikan cichlids, you can get away with a lot more and not have probs. I suggest using the play sand to anyone as a substrate its just simply the best stuff I have found. Once you establish the tank the sand doesn't stir up easily and takes a lot to cloud the water. As far as vaccuming, you basically just need to skim over the top of the sand and suck up any debris that lay on the top, since they don't readily penetrate the sand layer there isn't any need to for traditional gravel vaccuming. I love the stuff and won't use gravel again.