Those pics are showing how boat anchors/chains and people destroy reefs. In Hawaii they now have signs at the beaches warning people that they are destroying living coral if they step on it.
The smell that you smell at the bottom of low tide is the smell of decomposing dead stuff; stuff that died. Yes, in the wild, things die at low tide, but because this is a twice daily occurrence, many things don't live in that zone. Other organisms can protect themselves at low tide. Some move into a pocket of water to wait it out. Some cover themselves with a mucous coating to stay moist. Unfortunately, others get caught out of water and die. Some alga dry up and then rehydrate when the tide comes back in, to live again while other algae, or parts of the algae dies back.
Hermit crabs come out and eat that dead algae. Many other organisms come back out or come in from deeper water to feast on the stuff that the low tide left for dead. On the other hand, many organisms, especially birds come in at low tide to feast on the stuff that is now easier to catch.
The LR in our tanks is not accustomed to being out of the water. Most of the stuff that is growing on and in it cannot handle being out of water for long. Even more critical is the water that drains from so many small pores of the rock. Water is heavy and drains out easily, leaving air in it's place. Millions of tiny pores fill with air that, because of what is called surface tension, cannot refill with water without some kind of special action, like an invertebrate crawling through and pushing out the air bubble. Often, because of the position of the rock, the air rises into a cavity that has no route up and out. The cavity, which should be full of water but is now filled with air, becomes a prison which kills the sessile(non-movable) inverts living there.
This LR becomes a source of pollution that sends the entire tank through the cycle of death that has come to be known as the Nitrogen cycle.
The Nitrogen death cycle is a completely unnecessary situation which is so easy to avoid by utilizing the method described here.If you have ever pulled a piece of mature LR from your tank and noticed how water continues to drain from it for 2,3,4,or even 5 seconds, and drains again when inverted, you are experiencing the situation I have described. The only way I know of to avoid this is to use a bucket large enough to hold the LR and small enough to fit in the tank. This is a two handed operation.
Place the bucket in the tank, turn it sideways and slide the LR into it. Raise it out with enough water to cover the LR, and take it to the waiting container or new tank. I like to use the 4-5 quart the ice cream buckets. Carry it with two hands so the handle doesn't break. Lower the bucket down into the water, turn it sideways and slide out the rock.
This procedure will ensure that no air touches the LR and will guarantee that there will be no pollution cycle of the LR in the new tank. Of course some rocks are just too large to move this way. Sometimes this method is too impractical for various reasons. In these cases, the best thing I have found is fill a container ~1/2 full of tank water, prepared to quickly move the rock out of the tank and into the container. Once re-submerged, the LR should be turned, twisted and shaken to remove as many air bubbles as possible. Then move the container. At the destination, repeat the operation, turning, twisting and shaking the rock in it's new home. Sometimes it just means holding the dripping rock in a container and running it a short distance over to the waiting new tank, again turning, twisting and shaking the rock underwater before placing it in position in the aquascaping.
Oh, the question about which water to use is easily answered by observing that the LR is alive with all kinds of organisms living on and in it. It should be treated the same as a fish, a coral or an anemone. Acclimation. I will usually use half saltwater from the old tank and half from the new in the transport container, or do some kind of very quick acclimation. It becomes too much of a hassle to try and fully acclimate all that rock. That may be overdoing a bit as well.
I've been known to be a little obsessive.
In defense of my obsessive nature though, if you have ever moved rock the old fashioned way, not using this procedure and then try this procedure, you will see a very definite difference in the coming days and weeks. This method almost completely avoids the resulting Pollution Cycle. The LR never skips a beat in providing its full biofiltration capability in its new home.
Edited by Mark Peterson - July 08 2010 at 8:07pm