"John" wrote in message Hello.

I have a slightly strange question.

If I have just over 3KG of sand, what size of aquarium would I be able
to use this sand in as a substrate do you think?

Another option would be to use your sand in just part of the aquarium, and
thus have a larger tank than just that amount of sand would allow for. I
use different colour gravel in sections of my 4' tank, with driftwood and
slate dividers to keep the colours separate.