Lifetime of Live Rock

[steveg]

Hi there, maybe this is a silly question but I am curious to get some ideas on this:

Does live rock have a lifespan whereafter it will not perform the required function in a tank system and if so how frequently should one replace the rock in a system?

I have heard that 5 years is a reasonable time for fresh rock to be useful for, anyone had a tank for longer than that without changing any of the rock?

I look forward to your replies on this one.

Thanks

Steve

[fkshiu]

Mother Nature designed live rock to last for eons - no one changes out the LR in the ocean, in other words.

The issue in aquariums is that through poor husbandry habits and lack of maintenance your LR can become clogged with detritus and nuisance algae. LR works because its porous nature allows for anaerobic denitrification deep within its structures. With poor flow and enough crap, this denitrification can slow down or cease altogether. This is why proper flow and blasting LR with something like a turkey baster during water changes is recommended. This is also why the technique known as "cooking" LR is sometimes used whereby it is kept in the dark for extended periods of time to slough off algae and detritus is sometimes used to "re-charge" live rock.

You might want to check out PaulB's reef which is featured in this month's Reefkeeping Magazine online. His reef has been running continuously since the 70s with the same reverse flow undergravel filter and much of the same rock (both collected and manufactured).

[steveg]

Many thanks for your reply, I have heard of tanks that have mysteriously crashed after several years and I guess this is due to the rock no longer performing its function.

It stands to reason that if the porous nature of the rock is impeded by algae then the biological processes cease. Is it therefore reasonable to put older rock in the dark for a week so that the corraline and other algae die off or is that not long enough.

I am trying to decide between stocking my new tank with fresh rock from a system or getting some "used" rock at a better price? I guess if I can get some older rock from a tank, dump it in a vat with the lid on to cut out light it could be left for longer if necessary(with heater and circulation pump)

I would apprecaite your thoughts.

Thanks

[robert]

But, if you read this article written by PaulB, he says:

There is one more non-typical thing that I do that some may consider either risky or just useless. I mentioned above that I add bacteria from the sea to my tank. I feel bacteria are the most overlooked aspect of this hobby, and are vital to a healthy, long-lived tank. Bacteria cover everything in our tanks, but are they the correct bacteria for our purposes? Probably not. Bacteria enter our tanks in a number of various ways. Every time we put our hands into the water, we add bacteria. When we add fish, corals, rock or food, we add bacteria. The bacteria on the rocks and fish were at one time in the sea and “some” of those bacteria are the correct bacteria for our needs. But eventually, that bacteria will stop reproducing and will be outnumbered or outcompeted by other bacteria that may not be dangerous but do not necessarily help complete the nitrogen cycle. Why do so many people change so much water and still have nitrates? If we had the correct numbers and types of bacteria, we would never have to change water just to lower nitrates; the bacteria do that for us for free. I have found that by adding bacteria from the sea a few times a year, my reef stays healthy. I have no scientific data on this theory, but I do have a 40-year-old tank with an undergravel filter and no nitrates.

That might provide explanation why some tanks crash all of the sudden after many years of successful operation. Clogging by detritus and/or algae might not be really a problem. Killing of beneficial bacteria and bringing system to "Day 1" of cycle definitely would be a problem. Anyway, just another angle to look at this.

[hillegom]

Robert, so you are saying, when at the seashore, pick up a rock and put it into our aquariums? Or do you use mud?
Thanks

[JPotter]

Does the sea water and/or sand/mud/rock have to be from temperate sea water? I would expect so as bacteria are quite specific about environmental needs. Thus it will not be much help for those who live in colder regions. Hopefully I am wrong and will find it is OK for me to go down the street to get sea water or out on the boat to get away from poluton potential...then I would just heat it up to temp.

[steveg]

I read the article from PaulB, interesting stuff. The zeovit system has a bacterial addition which might work along the same lines.

Does the live sand in the stores not also address this?

I guess another option is to add or swop over a fresh piece of live rock periodically to ensure fresh seeding with the correct bacteria....

[Kronk]

I would think swapping a piece of rock or cup of sand with a fellow reefer would add as much or more diverse bacteria than picking something up off the beach... and you wouldnt get as much risk of polution, depending on the reefer

Ken

[steveg]

Assuming that the reef it comes from is in good condition without undesirable bactera?