Why You Should Use Live Rock

I post this a lot in different threads on different boards, so I am going lay my thoughts out to not derail other threads anymore. If you don't agree with my views, then cool.

Live rock is super important to the tank. It will lower nitrate and bond phosphate that later allows bacteria to swap the P off of the rock when it needs it to grow. When you buy live rock from the ocean, that live rock has bacteria and micro fauna all the way in the center that established over many years, is typically phosphate free and is ready for action. There is no substitute for this IMO.

Where you get the rock matters. Nice rock from the pacific is very light and will allow more bacteria and micro fauna to live in the rock. It typically costs more, but since it is lighter, it will take up more space for less money. The worst rock around IMO is the stuff mined out of quarries and left in the Atlantic for a few months to get some stuff on the outside - very little can live on the interior of this since it is so dense and most of the stuff on the outside dies anyway. A basketball sized rock from Marshall Island might weigh 6-8 pounds, so even at $9 a pound, that is cheaper than a 30 pound Atlantic rock the same size at $5 a pound.

Rock that looks good on the outside might not be doing it's job on the inside. Live rock is more than having coralline on it.

Dry rock used to have all of that micro fauna and bacteria, but now it is dead. It can take years for both the dead fauna and bacteria to fully leave the rock and then to repopulate to the center with beneficial organisms. Also, the decay from inside of the rock will pollute your tank and add excess N and P to the system - most of the P can get absorbed by calcium carbonate, but this will allow less absorption as your tank ages. Don't believe me? Break a piece of dry rock in half after a year and you can see where the new population starts and the old dead stuff is still in there. You can also dissolve some of the exterior parts of the rock in carbonated water or with acid and test for phosphate... it will likely be high.

Man Made Rock needs to populated with bacteria. Most companies do this for a few months before selling. The exterior of the rock has some bacteria and micro fauna on it. It is very dense. If you break a piece of it in half after a year, it is hard to see much bacteria and micro fauna... it looks like dense quarried rock. It is not as good of a filter IMO than more porous live rock. It should be phosphate free unlike dry rock.

Most people like man-made or dry rock because it has no pests. All that it takes is one frag plug to load your tank up with bryopsis, bubble algae, aiptasia and all other kinds of nastiness. If you appropriately cure ocean live rock the only really issues that come up regularly is the occasional mantis shrimp from Atlantic rock... and I guess even a Sunburst Anenome as a hitchhiker. Once you add your first coral, your sterile rock is gone and you better have a plan like everybody else to keep the nastiness at bay.

If your rock is nasty with algae and other pests, IMO you are better off cooking it in water for 3-6 months rather than acid bath or bleach it. It is not fast in the short term, but in the long term, the cooked rock will be pest free, phosphate free and ready for service as a filter. Good, porous, live rock will help keep your algae down since it works so well to combat nitrate and bind/swap P with bacteria taking it out of the water column until needed for growth.

Personally, I would use real live rock as the majority of rock in the system and limit the use of non-live-rock to special structures and arches and stuff where you really need it for cool shapes and stuff.

YMMV, but there is mine...

 

Good read thanks for sharing

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A container with no light with reef-strength saltwater and a heater. You do need oxygen. A maxi jet or Korallia is a good pump. The last time that I cooked a bunch of rock, I used a 44G brute with the lid mostly on that just let a bit of air exchange.

The bacteria and micro fauna in the rock will eat all of the waste/debris/algae/junk and also remove most the phosphate bound to the calcium carbonate. You don't need to do this with new live rock unless you are worried about hitchhikers, but most of those will be taken care of in the cycle.

After a few weeks, you will see all kinds of sludge on the bottom. Shake the rock in the old water, clean the sludge out and put the rock in new water. Old water-change water is good for this unless your parameters are way off. As time passes, you will get less and less sludge coming out or the rocks. After a few months, depending on how nasty the rock was, the rock will be bare on the outside, but ready to kick azz on the inside.

 

Good read thanks JDA!

 

Damn it!! I need a 'Like' button.

 

Great write up Doug!!!!! Thanks for writing this up!!! I just created a whole new Rock only section and added this as the first sticky

 

What are your thoughts about adding rock to an established tank from time time?

 

I add a lot of rock in the period of a year. I give a lot of coral away and most of it is on decent sized rock, so it kinda goes with the territory. I typically find a nice shipment of porous LR at a store and cherry pick 10-40 pounds at a time, depending on how nice it is. If it is cured already, I let it live in my sump until I need it. If not, I cure it - I don't wait since it might get sold. The last batch that I got was in Boulder from Vanatu. It is nice and light. I don't even care where it came from as long as it is from the pacific, has a good shape and is light (porous).

I had a friend in KC with a FOWLR who would rotate rock between his display and his cooking container every 3-4 months. This was a tank with nasty/sloppy predators that could get really ugly and need a 5G bucket of carbon a year to keep the water mostly clear. When he put fresh rock in and took nasty rock out, the water would get clearer and the nitrates and phosphates would both go back to near-reef levels for a while before it got gunked up again. The stuff that came out of the rock when he cooked it was really nasty.

 

jda123 is the man. Really good info!

 

I agree with you 100%! Nothing can beat natural live rock. :bravo:

 

where do you buy harvested live rock I thought most of it is aquacultured now a days

 

What are your thoughts on marinepure? Extremely porous and a very large surface area. The way water runs thru it, it should colonize much quicker, no?

 

All "Live Rock" from Florida is "farmed" or aquacultured. You can still get the "real-stuff" most commonly from Fiji and Tonga, but some also comes from Jakarta, Bali, Alor, Irian Jaya and Pohnpei. Although they're beginning to "farm" live rock through out the Pacific including Fiji and Tonga now! Also IMO that deep water rock is much better than shallow water rock.

 

Broke up some rock today and figured I'd share in case anybody has doubts about colonizing dry rock...

This is what the inside of quarried rock looks like after 18 months in a tank seeded with mature live rock. Essentially no life under that outer layer of rock.



The scape of my most recent build all but required I use dry rock...I did seed the tank with some live rock in the sump, but there is still a lot of "aging" to do as far as the rock in my display is concerned. I don't have any pics of what live rock that has been sitting in the ocean for decades looks like...but have cracked some open in the past...and the black/gray rock fully colonized with bacteria all the way through the center is unmistakable.

Great post, thanks for sharing jda!

 

Marco rock

 

Thank you Jahmic for posting these photos! And jda for bring this up! You can NOT do the "aging" of rock (aquacultered or farmed) that is equals to decades under the ocean! I've broken live rock open and immediately you'll see and smell the difference! I'm a BIG believer in real "live rock" for years! I've been doing saltwater for over 50 years now and (knock on wood) have not ever had a tank "crash" using REAL live rock. This has been "one of my secrets" for my success in my husbandry of saltwater. As most of you know, I'm setting up a new shop and guess what ....... we'll be cycling with REAL live rock!