As mentioned, beach sand is a hit or miss - with the risk much greater then the gain.
No telling for sure - unless you are a geologist - what the beach sand is made up of. I'd imagine most beach sand consists of ground up sea shells, quartz/silica, maybe some bits of old coral, dirt, chemical pollutants, decaying organic matter ...... whatever.
The whatever is the scary part. Not knowing for sure what you have there would lead me purchase a "known" composition of sand. The money and time you invest in setting up, maintaining and enjoying your tank is worth the bucks of buying quality sand. Plus - aragonite sands benifit your tanks pH and alkalinity down the road.
Or - get a bucket and shovel and "hope for the best".
Not worth it to me
Broomer
