FW question: Changing substrate

[SRT80]

Wanting to switch from sand to gravel. Currently have pool filter sand. Tank has been running for almost 3 years. I want to switch to a natural gravel.

What are my options? Drain tank, remove fish to a temp setup, and replace all substrate at one? Or maybe try and remove half and replace with gravel and let the tank run for a month or so then replace the other half?

Thanks,
Steve

 

[H@rry]

I'd be careful about using a substrate with such large particle size. Years ago I had a tank with crushed coral. After about 3 years it became so packed with detritus that I couldn't control the algae. I tore the tank down and replaced it with sugar sized aragonite sand.