Originally Posted by sundance2011
Basically what is the ideal depth for the substrate in my 80G reef tank and is crushed coral, sand or a combination the best? I have the substrate from my old setup (crushed coral mostly) but is it a good idea to reuse it considering the organic material left in it from before or can it be effectively washed by flushing it with water and agitating it at the same time?
What are your goals for the tank? A sand sifting critter will not be happy with crushed coral, but crushed coral is easier to clean than sand. Reusing old substrate from an active tank is fine. You may have another cycle after doing so, as the deeper buried organics get stirred up into the aerobic zone, so I would be careful about adding it if the tank is already occupied. Flushing out the excess organics might wash off or chlorinate the friendly bacteria. If adding to an established tank that might be a good thing, but if trying to get a new tank to cycle faster it would not be a good thing.