How to switch substrates gravel to sand

So my friend was explaining to me today saying how painted gravel poisoned her snails cuz they can eat the paint off etc and so I’d like to change my painted gravel to sand unfortunately I don’t want to wreck my cycle cause there’s fish that mean a lot to me in that tank and I can’t move them to a different tank I want to do this today and one of the fish is a pea puffer which I can’t just stick in my community tank ya know. Any tips would be amazing
It’s a 10 gallon btw

 

This is the easiest way. Less messy water.

 

This is the easiest way. Less messy water.

Ok thank you!

 

Im not positive the painted gravel killed her snail but I guess its possible. I think most people switch it out because it starts flaking and looks gross.

 

Im not positive the painted gravel killed her snail but I guess its possible. I think most people switch it out because it starts flaking and looks gross.

Ya i switched to sand this sounds weird but I mixed black and white sand together and it looks good

 

I have seen a lot of people do that. It does look good.