How to know live rocks from dead rocks when purchasing ?

For the sake of differentiation, I prefer to call that cured base rock.

One of my biggest pet peeves is to see a LFS throwing $2/lb dry rock into a tank of SW, then selling it as live rock for $10/lb when 1) it lacks the detritivorous micro and macro organisms found on true LR, and 2) you can have the very same thing by placing the $2/lb dry rock in your own tank.

JM2C

 

If you're referring to miracle snake oil products like Purple Up or Reef Accelerator, save your money. You shouldn't dose anything for which you cannot test, and you don't even know what's in that stuff.

FWIW, I started my tank with regular Instant Ocean salt mix and dry rock, and I've never dosed anything. When my CuC came in, a few snails had coralline on their shells, and in less than a month, it covered everything in my tank.

 

lol.. Bill thats funny. because i always notice how much coralline is on my snails. they are thick little purple snails now,

 

My way of find out if a live rock is "cured" is the smell. Usually it you have uncure live rock, it kinda smell like dead fish because all the dead bacteria. The well cured one are smell like fresh seaweed. At least that is one of my way to decide if the LFS's LR is ready to go in my QT.

 

Will Corraline grow on my rock?

Im not too sure but i have 15lbs of live rock with coralline and 30lbs of limerock that have been cured. Question is will coralline grow on the limerock? they are both made of the same calcium?!
Thanks!

 

When you say "limerock", do you mean terrestrial limestone or aragonite base rock? Some limestone such as "TX Holey Rock" is a lot more dense than aragonite, and IME, doesn't grow coralline as well.

As mentioned, if you keep your Ca and Mg levels correct, the coralline will grow. If you have another tank or a friend who has to scrape coralline from the tank panes, you can collect some of the "dust" and seed your tank with it.

 

You learn that quickly in this hobby!!

 

how to NOT know LR from base rock, is the real question lol.

 

Just like everyone said. I had half live and half dead rock in my tank at set up. I couldn't point to you the dead rock after a year. It all blends in.