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Discussion Starter · #1 ·
Okay, so admittedley i dont know a whole lot about salt water, but i do know how important live rock is. It acts as the major filter in the system

My question is what happens if we stick liverock in freshwater? Will it do the same thing?

I know live rock is expensive, and likley not worth the money in freshwater but i was wondering anyways :)

Alex
 

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Short answer: everything on the liverock will die and the stink will be so bad you won't be able to step into the room without gagging.
 

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i don't think there is live rock for freshwater.
live rock to me is like live coral and stuff on rock and it grows
 

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i think anything living in/on the live rock will die too(not the first time i heard about this) and yah..heard it will reek. kinda like exposing ourselves to caustic/hazardous environment without protection. not the best idea....

if you want something that look like a rock in your tank..think some places sell "dead rocks" ...or other ornaments that resemble rocks. unfortunately, i dun think anemones and yada will live on those rocks in freshwater
 

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Discussion Starter · #7 ·
okay reefers help me understand live rock. Its the bacteria that makes it "live" yes? So what does salt water have over freshwater in this?
 

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Yes, live rock is called "live" because of the bacteria but a lot of good rock also has other creatures living on it, such as sponges, macroalgae, polyps, anemones, corals, crabs, etc. If these are stuck in fw, they will die and rot. Your ammonia level will spike & the rotting biomass will stink. Everything in your tank will die.

Bacteria in fw will inhabit the rock as well, I'm quite certain, but the live rock will raise your pH levels and is very expensive if used for biological filtration. Any filter media will do a better job than live rock since more water flows through the filter media and more bacteria will live in the media (by area or volume) than it would in live rock sitting in the tank.

Huge waste of money. Live rock is very expensive. One of the biggest expenses when setting up a saltwater tank.

Anthony
 

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Discussion Starter · #9 ·
thanks for speaking my language anthony :)

Makes more sense now. I was never planning on going out and purchasing any but i just wanted to know why it is never used in FW
 

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Live rock doesn't exist in freshwater because corals and similar invertebrates never evolved in freshwater environments. Live rock is essentially calcified coral skeletons. And it is the internal structure of coral skeletons that enables live rock to work its magic.

Live rock is not only able to house nitrifying bacteria (any surface can do that in salt or freshwater), but it can also perform DEnitrification as well. In other words, it takes the nitrogen cycle another step further by reducing nitrates as well as processing ammonia and nitrite. It can do this because of the unique internal structure of coral skeletons which contain billions of teeny tiny microscopic chambers. These are so small that they are actually oxygen-starved and are thus able to perform anaerobic denitrification with a different set of bacteria. The internal surface area of live rock is greater by an order of magnitude than your common filter sponge. This is why when purchasing live rock you should purchase the least dense rock with plenty of holes.

Why did coral not evolve in freshwater? The answer is probably has to do with coral skeletons being primarily made of calcium carbonate which dissolves at a pH of around 6.6. This is why putting crushed coral into a FW tank is a popular way of increasing KH. Corals simply cannot live on a lower pH environment that freshwater bodies of water are at.
 

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AWW,
Although all the comments made here are true regarding live rock in FW, you can use rock such as lava rock or similar porous rocks as biological filters within the aquarium much the same way. Bacteria will colonize on and within the rock and control ammonia etc. We had a 40 gallon set up in this way for many months with simply an airstone and internal filter with floss. Most of the biological action was maintained by the lava rock. That being said, live rock does provide other benefits to a marine aquarium than the lava in FW but I thought it was an interesting point.
 
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