Substrate to sand

[el richie]

Well my fourty breaded has a 2 to3 inch "sand" bed but I don't like the way it looks anymore, was wondering if I could change it out in one hit or should I do it gradually.

 

[blackx-runner]

What are you planning to change it to. If you're looking at something coarse like a crushed coral substrate it can come with a different set of problems. If you're stuck on changing it out I always prefer to change things slowly over time in my tank. Suck out some with each water change over several weeks trying not to stir up things too much. Don't want to shock the system.