I think my lfs id lying...

[Zactheninja]

So I was at my lfs today and I was talking to the guy about live rock and he said that it would take me 12 weeks to cycle a tank with dry rock seeded with live rock.
I honestly think he's just trying to get me to buy more live rock from his shop....

 

[Beengirl]

How big is the tank? I just cycled my 30g in 11 days by using 80% dead rock and seeding it with LR from my 55g. Then I took some filter media from my 55g and put it in the filter of the 30g. I also added a cup of sand from my 55g. It was over quickly.

 

[Zactheninja]

100 gallon.

 

[Beengirl]

It's the same principle. I would buy mostly dead rock and seed it with a few pieces LR scattered around amongst the dead rock. If you have another tank or know someone with a tank, you could get add some sand from that tank (as long as you trust it's disease and parasite free) or add some filter media from another tank to yours. I've heard of some lfs giving people who are starting up a tank a cup of sand and/or old filter media when asked. Again, you'd have to trust their tanks. When I cycled my 55, just used live sand and all live rock (and a shrimp). It took 4 weeks to cycle. 12 weeks seems a little too long IMO.

 

[Mrc8858]

It took me 9-10 weeks to fully cycle with 100% base rock and no additives (fishless).

 

[Patrick125]

It depends on many conditions how long the cycle is...

 

[Ingy]

The truth is the more live rock you add, the faster the cycle should be. And you have nice looking rock faster too. The question is, what's it worth to you. If your LFS is giving it too you at even $5/lb that's over $500 (mine sells it at &10/lb) I've seen online sales for as little as 1$/lv for 50 lb boxes of base rock.
Plus, there's lots more options of types of base rocks for scaping with I think than your LFS likely has.