I would strongly recommmend waiting 48 hours. You want that
thing to hold and never leak, after all.

Marc


Chris wrote:

I want to install an overflow in my tank, i will cut and silicone the
glass for the box, now a question i can drain the tank to silicone the
box in place, but how long do i have to wait to replace the water? can i
start replacing the water after a couple of hours or do i have to wait a
few days?


--
Personal Page:
http://www.sparklingfloorservice.com/oanda/index.html
Business Page: http://www.sparklingfloorservice.com
Marine Hobbyist: http://www.melevsreef.com