I have also used the Quikrete play sand from Lowe's, and I have used Paverstone brand play sand from Walmart (which is NOT paver sand, that's a completely different thing), and I have also used another brand from The Home Depot, but the name is eluding me ATM. All the brands have been great, and since there is usually sand spilled on the floor at the store, you have a chance to feel the sand, rub it between your palms, to make sure that its not too sharp/abrasive. The color varies somewhat by batch, IME.
I think the problem I mentioned earlier with certain brands and types is that the sharpness varies by batch. If you choose to use a sand other than play sand, I would make sure you have a chance to feel it first. I don't know if a pocket magnifying glass might help, if you can't feel it.
If you use my method for cleaning play sand, which is messy and wasteful (and fun!) but produces very clean sand, I would use 3 50# bags of play sand.
You can also google close up images of the sand you want to buy. For example, this is pool filter sand:
You can see the grains are all roughly spherical and very smooth edged.
Below is CaribSea "Torpedo Beach Sand":
You can see that the grains are much more irregularly shaped and are sharper.
On this site, that sells kinds of sand for sand blasting (Clemtex.com - Abrasive Media | Black Beauty, Green Diamond, Green Lightning, Starblast XL, Garnet, Aluminum Oxide, ALOX, Steel Grit
) it states that "Black Beauty is a mineral slag that has sharp diamond-like cutting edges, and does not attract moisture, while providing fast cleaning rates, and an excellent anchor profile for a superior coating adhesion." Wow! "Sharp diamond-like cutting edges" is NOT something I would want my substrate fish on!