I am new to saltwater aquariums, and want to build a permanent
structure in my tank using plain old base rock. It is not live rock or
coral, but just the plain white dead rocks.  What I don't know, is
what would be a safe material to use to bond the rocks together to
build the tower. I saw a rock structure in a local pet store, and an
employee said he thought the guy used tile grout to build it.  I have
a two part question: 1) Is it safe to use tile grout to bond rocks
together in a saltwater tank?  2) What are some other materials I can
use to bond the rocks that is safe for saltwater that won't affect my
fish and the water?  There are sites out there that claim quick
concrete is good, but they are using it inrreef tanks with live rocks
and coral.  My system is FISH ONLY, no live anything.  Any help would
be greatly appreciated, and certainly, the more detail you can
provide, the happier I'll be =)

---

Request for Question Clarification by tlspiegel-ga on 10 May 2004 23:22 PDT

Hi sparkity,

I performed an extensive search on tile grout and also quick concrete
to be used for bonding base rock in a saltwater tank.  The only
information I found is to use Aquarium Silicone or a non-toxic 100%
silicone sealant appropriate for aquarium use, and to put the rock in
first before the fish.

Because I cannot confirm any information on tile grout or quick
concrete, I must allow you to be the judge as to whether this answers
your question.  Please let me know by clarification and if it does, I
will close (answer) your question if this is suitable.

Texas Holey Rock by Marc Elieson  
http://www.cichlid-forum.com/articles/tx_holey_rock.php

[edit]

"The second reason why I prefer it over other rocks is due to the fact
that it has numerous caves. Mbuna (i.e., rock-dwelling cichlids) are
very territorial. They love caves and little nooks where they can hide
from other equally-aggressive tank mates. Some of my Africans spend a
considerable amount of time swimming through these tunnels and most of
my Mbuna actually sleep in them. Furthermore, I have noticed that by
providing them with lots of caves, my dominant fish have claimed less
territory.

The most frequent question I get about these rocks is: Where can I get
some rocks like yours? If you live in Central Texas, it?s all over the
place. I have also heard reports that honeycomb limestone also exists
in Washington State and Florida. I wouldn't be surprised if it could
also be found in many other places. If you want to buy it, there are
several places on line, including Ebay.

Before you put these rocks in your tank, be sure to clean them with
bleach. And then be sure as heck to rinse that bleach off before you
put it in your tank with the fish. The sniff test works for me: if I
can smell it, I know it?s still got bleach on it. I have purchased
limestone that was purportedly "clean." When I got to cleaning it, I
found all kinds of dirt and roots in some of the holes of my
limestone. I was glad that I took the extra precaution. In fact, I
pulled a rock out to clean it after 6 months and found some dirt in
holes that I had missed when I initially cleaned it.

Because of the immense weight of your rocks, especially if they are
stacked, you should consider how they are placed in your tank. This is
especially important because your African Cichlids will dig and could
undermine a rock formation that could come tumbling down. To prevent
such a disaster, I glue rock formations together with silicone. Some
people use egg crates on the very bottom of their tanks, before laying
gravel. This prevents a rock from applying pressure to a single point
on the glass, which could lead to crack.

If you?re unable to find any honeycomb limestone, there are other
Cichlid-friendly rocks I recommend. These include slate, quartz,
petrified wood, lava, granite, tufa, "pagoda," and "lace rock."



Best regards,
tlspiegel

Hi sparkity,

I posted my clarification very late last night after stores were
closed.  Today I made several phone calls and all shop owners
recommended HoldFasT Epoxy Stick.

I was advised not to use tile grout or quick concrete for many
reasons, but the main concerns were toxicity to fish, in addition to
the breakdown factor over a period of time.  You wouldn't want either
of those things to happen.  In addition, no one I talked to had ever
heard of using that in an aquarium tank.

HoldFasT can be sanded or drilled after it's dried in 30 minutes.  I
would recommend using it or a safe Aquarium Silicone glue.

Here is the information on HoldFasT:


WetPetsUSA
http://shop.store.yahoo.com/wetpetsusa/aqsyhoepstfo.html

The HoldFasT epoxy stick has superior bonding ability that allows you
to create steps, caves, cliffs, and walls for aquarium animals to
enjoy. It bonds all types of materials from rocks, to corals, to
slate, and many more. HoldFasT epoxy stick is non-toxic to fish and
invertebrates and is great for use in freshwater or saltwater.
HoldFasT epoxy stick mixes easily in the palm of your hand. No messy
liquids to measure and mix just break off a piece, knead it in your
hand until it turns white, and it is ready to bond.

Availability: Usually ships the same business day.

Aquarium Systems HoldFast epoxy stick for aquariums
$10.39

Wet Pets USA
520 Hartford Tnpk
Vernon, CT. 06066
(860) 875-8265

=================================================

http://www.aquatichouse.com/Maintenance_files/Epoxy.asp

HoldFast brand epoxy stick for aquariums 

The HoldFasT epoxy stick has superior bonding ability that allows you
to create steps, caves, cliffs, and walls for aquarium animals to
enjoy. It bonds all types of materials from rocks, to corals, to
slate, and many more.

HoldFasT epoxy stick is non-toxic to fish and invertebrates and is
great for use in freshwater or saltwater.

HoldFasT epoxy stick mixes easily in the palm of your hand. No messy
liquids to measure and mix just break off a piece, knead it in your
hand until it turns white, and it is ready to bond.

$8.95 

=================================================

http://saltaquarium.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.aquariumsystems.com%2Faccessor.htm%23HOLDFASTTM%20epoxy%20stick

$12.00 



Best regards,
tlspiegel

Thank you very very much...not only did you go beyond the standard
service to answer my question, but you also inadvertently tipped me
off to "texas holey rock," which I amn definitely interested in,
thanks to you.  Mahalo nui loa!!

Hi sparkity,

Thank you very much for the 5 star rating, comments and generous tip! 
Have fun with your new aquarium... it's going to be beauuutiful!  :)

Best regards,
tlspiegel