vac cruched coral

[fla pat]

I have crushed coral and would like to know when I vac the cc do I vac the hole tank or just do half and vac the other half at the next water change. I do monthly water changes on my 90 gal fish only tank.
I know that sand is better but don't some of the same denitrafication things take place in cc as well as sand?:notsure:

 

[daniel411]

When I had a 90g set up with crushed coral, I'd just keep vacuuming till I filled up a 5 gallon bucket with gunk. Sometimes I cleaned the whole tank, other times just sections of it.
To my knowledge crushed coral wouldn't be able to have the anaerobic areas like sand can to facilitate dentratification.