Cycling with live rock

[Dlc27]

Ive read up on this, and I think I've got my answer already, but I'm hoping to get some real experience feedback from you guys. Having come from a freshwater background I've always done fishless cycling on new tanks. The saltwater world seems to be a bit different by cycling with live rock. My question is for those of you that acquired desirable hitchhikers on your live rock, did you soft cycle them? If so, was it touch and go? Did they make it? How long did it take to cycle?

[seabass]

Soft cycle is a term used when people perform water changes to try to lower ammonia levels (in an attempt to save more beneficial life) when the cycle is still becoming established. But in reality, ammonia levels are only temporarily lowered and they promptly rise back to levels as if no water change where done at all. This action will slightly lengthen the time it takes for the cycle to become established.

However, once the ammonia levels start to drop on their own, water changes have a positive result on lowering nitrite and ammonia.

 

Live rock is an ammonia source. The ammonia comes either from die off of life from transport or from the living organisms on the rock. However, the rock is also the biofilter (the home to the nitrifying bacteria). Ammonia spikes occur when more ammonia is being produced than the nitrifying bacteria can process. However, in cases where the rock has already been cured/cycled, the biofilter can process the ammonia coming from the rock (so the cycle is already established for this limited bioload).

 

Once the ammonia becomes underectable (I suggest for a week straight), you can slowly introduce livestock to increase the bioload. This is usually done by adding a small cleanup crew. I suggest waiting another week (monitoring ammonia to make sure it remains undetectable) before adding a fish. Livestock additions are followed by waiting periods which allow the bacteria populations to adjust to the new bioloads.

 

How long does it take before the rock can process it's own ammonia production? It depends on how much die off has recently occurred on the rock and how well established the bacteria populations are. Fully cured live rock from a local source should not experience an ammonia spike at all (if transported in saltwater). Note that local stores rarely bag their rock, so (if you live more than a few miles away) bring a bucket of saltwater to transfer it (the short time out of the water to get to the car will not impact the rock/life at all).

 

Uncured rock (rock that has just been shipped to you or your local store) will have die off. The amount of dead organic material, the nitrifying bacteria populations, and the resulting ammonia level will all play a part in how long it takes before the rock can process its own ammonia production (for the nitrogen cycle to become established). This can take over a month.

So you will wait as short as a week, to over a month, in order to be sure that ammonia is not detectable before adding additional livestock.

[Partially Submerged]

The main difference between freshwater and reef tanks in terms of cycling is that there is a lot more alive in reef tanks when you start them with live rock. As seabass said, you already have an ammonia source and you'll already have a significant population of beneficial bacteria. If the live rock is cured and fresh from the LSF, you may not notice any ammonia spikes at all. Compare this to a new freshwater setup, which is usually pretty barren of life. To kick off a cycle you pretty much need an external ammonia source, and it can take much longer for ammonia and nitrite to go down again because your ecosystem has to start from scratch.

[Dlc27]

Soft cycle is a term used when people perform water changes to try to lower ammonia levels (in an attempt to save more beneficial life) when the cycle is still becoming established. But in reality, ammonia levels are only temporarily lowered and they promptly rise back to levels as if no water change where done at all. This action will slightly lengthen the time it takes for the cycle to become established.However, once the ammonia levels start to drop on their own, water changes have a positive result on lowering nitrite and ammonia.

So basically it's not really helping anything to do a "soft cycle". It's not really possible to keep the ammonia levels down to a minimum? I know I'll have a cycle since my rock is being shipped.

[seabass]

Here is the testing that I did which demonstrates that water changes don't actually lower ammonia and nitrite levels until they start to go down on there own: http://www.nano-reef.com/topic/206500-part-2-water-changes-during-the-cycle/

[Dlc27]

Thank you for all the information.