Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
If the tap water is already pretty high, and the GH and KH, too, then the trace amount of aragonite will not make any difference at all.
I get a lot of the substrate out with various scoops, but I like a 1 quart square food storage container. Flat sides do a very good job of pick up off the floor of the tank, and the rounded corners fit pretty well into the siliconed corners.
For those last grains, a paper towel is really good.