is adding dry rock or sand to an already cycled tank a bad thing?

[castrojc]

I am wondering if this will start the cycle process all over or if it wouldn't make a difference?

[thegrun]

It may be fine but it can also start a new cycle. If there is a lot of dried organics in the rock or sand it has the potential to start a new cycle. The safest thing to do is cycle the new rock and sand in a separate container and then add it to your tank without worry. Next would be to add 10% or less of your current amount to your tank at a time, waiting 10 days between additions. The third option is to just add it and pray!

[Zappo]

How big is the tank, how much rock do you already have, and how much rock are you thinking of adding? Dropping a 5lb dry rock into a 90 gallon reef won't make much of a difference as long as it's been scrubbed clean. I do it from time to time when adding small rocks to stick corals on and it's never been a problem. Adding a substantial amount of rock, on the other hand, can be risky and it's worth cycling it outside the tank first.

[castrojc]

How big is the tank, how much rock do you already have, and how much rock are you thinking of adding? Dropping a 5lb dry rock into a 90 gallon reef won't make much of a difference as long as it's been scrubbed clean. I do it from time to time when adding small rocks to stick corals on and it's never been a problem. Adding a substantial amount of rock, on the other hand, can be risky and it's worth cycling it outside the tank first.

I have a 46g and about 50lbs in there... I would like to add another 30lbs or so and right now there is no sand at all, I am planning on putting about an 1in of sand in there...

[b0bab0ey]

I have a 46g and about 50lbs in there... I would like to add another 30lbs or so and right now there is no sand at all, I am planning on putting about an 1in of sand in there...

Just add very slowly and you'll be fine. Start with about 1/2 in of sand and 10 lbs of rock. Wait one full month, and add the rest of the sand and 10 more lbs of rock. Wait another month before adding the last 10 lbs of rock. This plan might be overly conservative, but why risk it?