February 1996

Well as promised, this month I will be answering some of
your letters. Unfortunately I get so many it is impossible
for me to answer each and every one of them so in the
future I will try to condense them into a single letter
when I find common problems.

Q. In recent months, my Catalaphyllia jardinei has
slowly been shrinking. I've had this specific coral for
more than a year. Other corals in the reef tank are showing
no signs of stress or demise. I feed the elegance small
pieces of freshly chopped clam and small chunks of frozen
brineshrimp. The location of the coral is approximately 4
to 6 inches from the surface of the water and it is in a
medium to low flow of water current. It seems as though the
skeletal portion of the coral is slowly "chipping" away and
seems to be getting smaller also. The specifics of the tank
are as follows: nitrates = 0 to 0.01 ppm, phosphates = 0 to
0.01 ppm, ammonia and nitrites = 0 ppm. Specific gravity =
1.023. Temperature ranges between 78 to 80 degrees F (no
heater in water). The tank is grounded. The size of the
tank is fifty gallons with 50 to 75 pounds of Marshall and
Solomon Island rock. There are three four foot VHO bulbs -
two Actinic 03's and a 50/50. I run a Venturi protein
skimmer with a large pump driving it and there isn't a
wet/dry filter. I slowly add kalkwasser during the night,
and all make-up water is R/O. I perform a five gallon water
change every five days with R/O water, which has proven to
be very successful. I use a top quality carbon by Kent
Marine in a Magnum 350. Water is circulated in the tank by
a PVC pipe with fine holes drilled closely together and a
submersible pump driving the flow.

My only fish is a healthy Zebrasoma xanthurum who has
been in the tank for about 4 months. Other corals include;
bubble, hammer, frog spawn, a Tridacna crocea clam,
Tridacna clam, and a Goniopora which has
multiplied itself. All eagerly accept food, (outside
flowerpot) and are doing well.

Thank you Dave Cataldo

Dave, from the list of corals you have provided it appears
you have primarily a lagoon coral tank. All those species
are commonly found in lagoon environments. These areas are
commonly characterized by elevated nutrient levels, reduced
water motion and often turbid conditions.
Catalaphyllia are found in sandy bottoms usually in
seagrass beds. They are not what you would normally
consider "reef" corals as such they are best located on the
bottom of the tank in the substratum provided they get
enough light down there. I have a few ideas as to why you
are having problems with the Elegans coral but your letter
lacked some key information. It would have been useful to
know the calcium, alkalinity and pH levels in your aquarium
for example. You also did not mention if you were adding
strontium, iodide or any other supplements.

I suspect a part of the problem may be that you are killing
your coral with kindness. Although feeding corals can
certainly be beneficial, it may be that you are
overfeeding. However, you do not 
state how often you feed
so it is difficult to say this is definitely the problem.
If you are feeding more than once a week or even twice a
month. I would suggest cutting back.

I am not sure what you mean when you say the coral skeleton
is being slowly "chipped" away. This sounds like you may
have some predation going on. Have you checked for crabs in
your tank? Check late at night with a flashlight to see if
there is anything damaging the coral.

Finally, a 10% water change every five days sounds a bit
excessive to me but if you have success with this, then
fine, but have you tried less frequent changes? Have you
tried moving the coral to another location in the tank? It
may be that it is receiving too much light or UV that close
to the lamps. Do not hesitate to move a coral to another
location if it is not doing well.

Q. I have recently re-setup a salt water tank after 18 years
of being away from the hobby. Boy, have I been away a long
time! Anyway, I thought that putting the old reliable
undergravel filter (UGF) in with powerheads was good and I
purchased a Fluval 303 for mechanical filtration and I
thought I was cool to go. Not! So after a few weeks of just
damselfish I put in a yellow tang and a banded shrimp. I
was having to do 50% water changes every 2 weeks to keep my
nitrate levels down below 30. Since then I have read a lot
(Thiel, Sprung, Moe) and am convinced further, after
discussing the problem with a local tropical dealer, that
the problem is the undergravel filter which I am in the
process of tearing out over the next month. I also
installed a wet/dry trickle filter to do the bio-filtering
thing whilst the under gravel is being taken out. Now that
that's out of the way....When can I start to put in live
rock to start a reef tank? Do my nitrate levels have to be
zero? What testing kit do I need? Are those kits necessary
that test everything (silicate, strontium, magnesium, iron,
iodide, KH, Ca++, phosphate, dissolved O2, C02) or can you
get by with 6 of the 10? And which ones?

Darryl J. Nelson

Darryl, you have discovered a new approach to setting up a
reef tank ... no live rock! I am not sure what your
retailer suggested to you but replacing your UGF with a
trickle filter was not going to help you if your goal was
to reduce the nitrate levels in your tank. Given the setup
you now have you will not reduce nitrates, they will only
continue to climb since the trickle filter is a very
effective nitrifying machine! Now you could cycle the tank
with the trickle filter and then add the live rock, this is
not a problem and will work. Whether you intended to do
this or not I am not sure because I would not have added
any fish or inverts until the live rock had been added and
the tank was checked to make sure if had not cycled again.
The live rock should reduce the nitrate levels over time.

A much better way would have been to cycle the trickle
filter separately by running it isolated from the tank so
that it recirculates. This is done by directing the outflow
of the sump back into the top of the trickle filter. You
would then add a seed culture of bacteria from another
tank or a commercial preparation, and then add an inorganic
source of ammonia such as ammonium chloride; there are
several such solutions on the market. Once the filter had
cycled you would discard the filter water (eliminating any
accumulated nitrates) and refill with new seawater. You
would then hook this filter up to your tank containing the
live rock and there you have a conditioned filter ready
without any nitrates added to the tank.

This is the way I setup my very first reef tank in the
80's, but it is not what I would do now. I would not use a
trickle filter and would instead invest my time and money
into a well-designed and functional protein skimmer. I
strongly urge you to invest in this piece of equipment. The
protein skimmer will remove many of the compounds that will
eventually contribute to nitrates in the tank, while the
live rock will provide more than enough biological
nitrification and denitrification. If you have read many of
Julian Sprung's columns, or my series of articles on
setting up a reef tank in AFM in 1990, this approach should
be familiar to you. Julian and I also cover this in detail
in our book The Reef Aquarium and my AFM articles are
available on my website (www2.hawaii.edu/~delbeek).

Finally some quick answers to your last questions. Your
nitrate levels do not have to be zero, below 40 ppm will
yield good results but lower is better. To begin the tank
you should have an ammonia, and nitrate kit. You should
also purchase calcium and alkalinity test kits. Although a
pH kit is also a necessity, it is much more economical to
purchase a pH meter as you will want to monitor this
parameter frequently and constantly buying test kit refills
adds up over time. A pH meter will allow you to better
understand the changes in your system and monitor the
additions of solutions such as calcium hydroxide
(kalkwasser). A phosphate kit may also be of use if you
encounter algae problems.

Welcome back to the hobby Darryl, you will only get more
and more confused as you go on ... but the rewards are
worth it!

Next month I will discuss probably the most common question
I get ... "I can not detect any phosphate in my water but I
have problem algae everywhere ... why?".