Place a handful or two in a clean (new) bucket. Run it under the tap so the bucket fills and overflows. (adjust the flow so the sand does not come out as well.) Dust etc. will come to the top and flow out. When it looks clear, tip water out and transfer sand to your tank. Repeat until all your sand is done. Any chlorine etc in the water with the sand will be nutrified when you finally fill up with dechlorinated water
now i got a question about this
i knew about that method, but when it comes to using one of those gravel vacuum's, does it leave the sand behind? i was thinking my convicts might like sand better than the rounded natural gravel, well i'd like a change too.