Changing tanks

[cidbozek]

Looking for opinions. I have two tanks plumbed to one sump, 90 and 29 both mixed reefs with about one inch sandbeds. I want to change out the 29 to a 40, using all the current live rock but with new sand. Will this cause a cycle?

[hollister]

If its base sand and you use all the water from the old tank you should see little to know difference.

[thegrun]

+1, don't use "live" sand, use dry (washed) sand and you will not have any problems. If you add a small amount of live rock (< 15 pounds) given the overall system size that should be fine also.

[cidbozek]

I will be using dry sand, and the current two yr old live rock. Draining 29 into Rubbermaid and putting live rock in it also, then switching tanks and plumbing, maybe about two hrs