Questions about LR & LS in new tank

Hi All,

I am studying up in preparation to start a 15 to 20 gallon marine tank
with live rock, live sand, corals, shrimp and a small fish. Also
planning to use an Eheim canister filter and protein skimmer (unless
of course I'm advised otherwise). I've read a bunch of posts here as
well as the FAQ's.

The guy at the LFS is very informative and patient. The tanks in his
shop look great - I think he knows what he's talking about, though I'm
new to marine tanks.

I've been reading about live sand and have this question: How can the
sand at the bottom of the sand bed remain alive? Assuming there is no
under gravel filtering (which I do not plan to use). Doesn't ammonia
and nitrite have to flow past this sand to keep the bacteria alive and
well? If not, then why doesn't just ordinary non-live sand become
live sand naturally by just sitting at the bottom of a tank?

Another question I have is (and I know this probably sounds naive
but)if I buy live rock from the store, from a tank that looks clean,
does it absolutely need to be cleaned before putting into my tank. If
it looks clean to begin with, what exactly do I clean off of it?

Thirdly, if I put live sand in a completely empty tank (well with only
water in it) how can I assure that the sand will remain alive before I
put anything else in it (whether it's live rock or fish)? For that
matter how can I be assured the sand is indeed live when I purchase
it?

In general, I'm concerned about the sequence and timing of putting
this stuff into a new tank.

Regareds,

-MB

How can the
sand at the bottom of the sand bed remain alive?

Gravity causes nutrients to fall to the bottom, where organisms utilize them.
You necessarily wont have a lot of 'flow' going past the sand, but it is being
mixed by the organisms in it. I have a fighting conch that burrows into the
sand for this purpose. I'd highly recommend one, their neat little fellas.

If not, then why doesn't just ordinary non-live sand become
live sand naturally by just sitting at the bottom of a tank?

It does, just not as fast and with less variety of organisms. Buy the sand
bagged, then get a cup or two of live sand to 'seed' your 'dead' sand from your
LFS or reef buddy. Dump it in one corner so it can breed. This will increase
your variety of life.

Another question I have is (and I know this probably sounds naive
but)if I buy live rock from the store, from a tank that looks clean,
does it absolutely need to be cleaned before putting into my tank. If
it looks clean to begin with, what exactly do I clean off of it?

I'm new to this too. I didnt clean mine. I've read that you should smell the
rock and look for decaying matter, scrub that off. You dont want the rock too
clean because like the live sand, theres organisms living in and on it.

Thirdly, if I put live sand in a completely empty tank (well with only
water in it) how can I assure that the sand will remain alive before I
put anything else in it (whether it's live rock or fish)? For that
matter how can I be assured the sand is indeed live when I purchase
it?

The sand would stay alive as long as your parameters dont go out of whack, i.e.
temp. salinty etc. One of my LFS's keep's their imported live sand in an unlit
tank with just about 4" of water above it. I noticed after adding live sand to
my prexisting dead sand that on the edges of glass you will see burrows that
have been dug by worms. I guess you could tell its live that way, otherwise
everything is just so micro, it'd be hard to quantify that.
~John

John, thanks for the reply. That information is very useful.

One other question I have is that I read somewhere that you shouldn't
put rock on top of live sand(???) They said that it would kill the
sand and create toxic matter. Is this true? If I'm using live sand
from the start in my tank, how would I possibly avoid putting rocks
(live rock in this case) on top of the sand?!

Regareds,

- MB

They said that it would kill the
sand and create toxic matter

I have yet to read this, but I'm 6 months into this too as a newbie. The
reasons I heard for putting rocks in first was for stability. If you get a
sand burrowing animal go under one of your rocks, they could all topple.

On the otherhand I think I do remember reading something about 'dead' zones in
the sand where sulfur and other bad things can build up. Not sure if this was
under people's rocks or just in deep parts of the sand.

I added my sand first before rocks because I didnt know any different at the
time Instead I just pushed the sand out of the way before setting down the
rock, then twist it back and forth several times so it settles.
~John