How much live vs. dead rock

[Glimmerman911]

I am going to be re-starting in the hobby soon, with a tank 50-75 gallons.

I have lots and lots of dead rock from previous tanks, hundreds of pounds.

My questions is, to cycle my tank, how much live rock will I need to get the beneficial bacteria I need? Will a small chunk work?

The sand I will be using will be dead sand as well, also from old tanks.

[crazinezz978]

wash it good! i would do 75 % base 25% live

[Glimmerman911]

I was hoping to get away with less live rock.

I am ok with the cycle taking longer due to the longer time period for bacteria to replicate onto the base rock.

Anyone been successful with 10% or even less?

[wooden_reefer]

To cycle the dead rock for a tank, very little bacteria seed is needed. Cycling is the intense cultivation of nitrification bacteria on to a medium of filtration, in this case your rock. You need only to add ammonia source to fuel the cycle. 99% dead and 1% live is good.

Later, greater diversity in microbial lives will develop as you add livestock, including lives on recently collected or cultured LR. The establishment of robust or excess nitrification activity to start will never interfere with greater microbial diversity later in a DT.

[Glimmerman911]

Sounds good, thank you.

I will re-join the local reef club to trade frags/rock/sand once I am up and running to get a greater variety of life into my tank.

[Fizz71]

To cycle the dead rock for a tank, very little bacteria seed is needed. Cycling is the intense cultivation of nitrification bacteria on to a medium of filtration, in this case your rock. You need only to add ammonia source to fuel the cycle. 99% dead and 1% live is good.

+1 on that.

In the old days they used bio-balls with no live rock at all. I know bio-balls are a no-no most cases today but I mention it to illustrate the point that a totally barren substance will eventually contain life given a starting culture and time.

[lowlt]

that's what I plan to to do in my next setup. 99% dead and look for a good live piece.

[Rhizo]

IMO 75% LR is best. Your tank is less likely to crash, unless you can honestly say you are an experienced hobbyist.

[Glimmerman911]

I would consider myself an experienced hobbyist, at one time I ran a 180gallon in wall tank with 120 gallon sump, 20 gallon fuge, and 50gallon grow out tank with auto top off switches connected through RODI with electronic solenoid. Plus calc reactor and UV.

I will do 99% dead and 1 good live piece, plus add more live pieces once the tank is more stable.

Thanks for the input everyone, will start a tank thread once I get going.
First I need a job and to finish the bathroom reno, so the wife sais! lol

[wooden_reefer]

At the very early stages of a cycle, bacteria population increases slowly in absolute numbers, 4, 8, 16, ... still very small until it gets toward the end, then the bacteria population will manifestedly increase very fast toward the last few days or the last week of the cycle. This is depicted by the rapid rise or fall of nitrite, for nitrosonomas and nitrobacter respectively.

It is very easy to understand why the starting population of bacteria at the start of the cycle is not important, as long as it is not too close to zero to chance having no viable bacteria.

[DevilBoy]

Could this be the reason why my cycling tank has been so hazy?? I have about 50 pounds base rock and 20 pounds bali alor live rock.

[Rhizo]

I would consider myself an experienced hobbyist, at one time I ran a 180gallon in wall tank with 120 gallon sump, 20 gallon fuge, and 50gallon grow out tank with auto top off switches connected through RODI with electronic solenoid. Plus calc reactor and UV.


If you feel confident, go for it :thumbsup: Although 1% seems awfully small. Dont you think? 25% maybe? Then again it is your reef tank :)

Could this be the reason why my cycling tank has been so hazy?? I have about 50 pounds base rock and 20 pounds bali alor live rock.

Is that on your 90G? If so, yes. You have to consider that LR has bacteria that has been settled there for years. It's not like we can pick a rock from the ocean and say, " Hmmm... this seems to be 5 years old :hmm3:." You can't expect dead rock to be of equal bacterial value because it went through a cycle. Just my .02

[bkaradza]

If you have time to wait for proper cycling you can put 90% dead rock and 10% live rock. But question is do you live near sea and put real sea in tank or you make water. If you put real sea water you can put 100% dead rock since bacterias are found in sea. If you make water then you need some live rock..

[bertoni]

You can use 100% dead rock if you want, and add some cultures of small animals later, if you want, or just do without them. A small piece of live rock might add enough, for that matter.

There's no need for live rock or sea water. Bacterial will come for free if you're patient, but a small piece of live rock for seeding might (or might not) speed the process. I've never seen any objective data either way on that.

[wooden_reefer]

There can be some question about some genetic diversity for nitrification bacteria. Some are more sensitive to copper or some antibiotics, and later a certain strain may dominate.

I doubt if 1% live rock does not already provide such diversity. I won't accept 100 bacteria as sufficient for such diversity, but 1 % live rock is plenty of genetic diversity.

[seattlerob]

FWIW, I started my tank back in oct, 09 with 100% dead rock. As of now, coralline taking hold & pods, etc can be seen roaming around everywhere.

[wooden_reefer]

You can use 100% dead rock if you want, and add some cultures of small animals later, if you want, or just do without them. A small piece of live rock might add enough, for that matter.

There's no need for live rock or sea water. Bacterial will come for free if you're patient, but a small piece of live rock for seeding might (or might not) speed the process. I've never seen any objective data either way on that.

Microbes responsible for decay come from air for sure, but nitrification bacteria may have to be introduced in an aqueous medium, possibly.

I have never had the patience to just wait and wait, so I can't know for sure.

[bertoni]

Lots of people set up quarantine tanks without live rock or bacterial cultures. Bacteria are everywhere. :)

[customdrum]

if you can, get some rubble or sand from a rock tank at a local store.
im about to do about the same thing but im gonna go get 4-5 cups of sand and rubble from a local store thats full of bacteria to help seed the tank. you can also take some live rock and scrubb it in the new tank to seed the algae in the new tank.

[wooden_reefer]

Lots of people set up quarantine tanks without live rock or bacterial cultures. Bacteria are everywhere. :)

bacteria also come from livestock and the water that comes with it.

[Fizz71]

FWIW, I started my tank back in oct, 09 with 100% dead rock. As of now, coralline taking hold & pods, etc can be seen roaming around everywhere.

I'm curious...how big is your system, how many lbs of dead rock and how many fish do you currently support?

I only ask because there is very little research on how FAST dead rock becomes as usefull as live rock is right off the bat. It'd be nice to know one "test case" for it. :)

[seattlerob]

I'm curious...how big is your system, how many lbs of dead rock and how many fish do you currently support?

I only ask because there is very little research on how FAST dead rock becomes as usefull as live rock is right off the bat. It'd be nice to know one "test case" for it. :)

My tank is 93g (30"x30"x24") with maybe 20g sump. I used just under 100lbs of dead rock, of which some was used to make my foam rock wall, and the remainder as normal rock structure.

After I setup my tank and let it cycle 30 days (although there wasn't much of a cycle that I saw) I added 2 fish from my old tank, and shortly after I added a pretty big CUC (around 100 hermit crabs & 100 snails). I kept it pretty slow for the next 30 days or so...

Since then, I now have 6 fish total (2 gsm clowns, 1 brown tang, 3 firefish), the same CUC, some SPS, LPS, and even a couple of softies.

Coralline is growing everywhere on the starboard bottom, and is definitely coloring up the rock as well. Little 'pods' can be seen crawling all over the rock at night, and also in the overflow and sump.

All in all, I'd say that the initial cycle was short to non-existant, which kind of makes sense since there was no "die-off". But, after adding the livestock I think there was a period of time where the pods & micro-critters were developing, coralline was starting to grow, and bateria in general were growing that most likely took longer to achieve compared to a system started with live rock.

Now at the 5 month mark, I would guess that my system probably still has less "live" in the "live rock" than what you'd get from buying real "live rock", but that's just a guess...based mainly on the amount of coralline I see on the rock...

HTH,

Rob