Cycled Rocks

[Starka]

Ok so when I went to Petco today, I noticed they had a huge bag of rocks that was on sale. When I picked up the bag it actually had water in it! On the outside said that the rocks were cycled and could be placed directly in the tank.
I have never heard of this before. So I wanted to ask to see if any of you had any experance with these rocks and if they work?

 

[HN1]

IMO/E, "cycled" rocks or sand from a bag are generally a waste of money. Different story if they come from a healthy tank. Ask about the source.

 

[mfdrookie516]

Is it something like this? CaribSea Dry Aragonite | Aragamax Sugar Sized Sand | Aragamax Select | Seaflor Special Grade Reef Sand | Fiji Pink Reef Sand | Flamingo Reef Sand | Bermuda Pink | Grand Bahamas Biome | Super Reef

 

[Starka]

Ya, it's like that just a different brand. For a small bag it was like $20, it was on sale too!
I think it is a great idea if it worked, but not knowing the process it was cycled could be harmful right? Chemicals and such?

 

[mfdrookie516]

No, it's not going to be harmful.. but the effectiveness would be highly questionable.

 

[miles]

The bacteria that's supposed to live in your filter requires oxygen and food (ammonia and nitrite) to survive. It cannot live without food for more than ~48 hours, and I'm not sure about oxygen but I can't imagine it's very long either. So it stands to reason that the good, aerobic (oxygen using) bacteria that might have present on the rocks when it was packaged will be long dead by the time the rocks get to you, and potentially replaced by anaerobic strains (ones that do not use oxygen). The anaerobic bacterias are much less efficient at what they do (converting ammonia to nitrite to nitrate) and are said to create an unstable, unreliable biofilter.

There's all sorts of speculation about the aerobic bacteria going "dormant" and "hibernating" while it's in the bag, but it's a pretty big gamble. In my humble opinion, you should save yourself some potential headache (and $20) and get a hold of some fresh "cycled" material. Media straight from the filter of a healthy, cycled tank will be your best option to speed up the cycle (though nothing will cycle your tank "instantly") and even a small bag of gravel or some plants from a cycled tank will help.

I'm having success with the "active" filter sponge from this website that is supposed to contain the bacteria, and I believe the sponges to be way more effective than bottled bacteria (which I've tried, unfortunately..), but is still not as good as fresh filter media from a cycled tank. I hope this helps. Good luck!

 

[jetajockey]

I disagree about bacteria dying off in that short of a period, but that's a different subject in itself. I do agree that 'cycled rocks' are probably no different than the 'instant aquarium' line by caribsea which has 'live nitrifying bacteria' in it. I asked Caribsea support and they told me that there is no organic material in their substrate, for one, but having anything but your sludge remover type heterotrophs in there would require the package to have a very limited (and dated) shelf life, or refrigeration.

The short answer is, get some real cycled media.

 

[Starka]

Thanks all for the help!