Is playground sand from Home Depot okay or do I need filter or special sand? I use the playground sand for my land hermit crabs with no problems... Just for reference.
Most pool/play sands are silica based so, in using them you may have a short duration diatom bloom. After that, they will not alter the water chemistry.
Some sands are calcium based. The easy way to check if there is a calcium component in the sand is to place a small amount of the sand in a glass container and add some distilled white vinegar. If it fizzes it has calcium in it. The greater the fizzing, the greater the calcium portion. These sand are usually sold as "NOT RECOMMENDED FOR AQUARIUM USE" because of a lawsuit years ago. The same company that mines sand sold for reef tanks was packaging it simply as play sand "sterilized, from the Caribbean". Since the play sand was selling at $4-$5 for a 50 pound bag while reef tank sand was selling for $30-$45 for a 30 pound bag, the reef tank companies got upset. I still see the stuff sold as play sand at my local supermarket. These sands are a good addition to hardwater tanks as they will keep the tank buffered.
Charlie