sand, and 500 watts of metal halide lighting
that I keep on for 10 hours a day. I also
have a large skimmer.
My ammonia, nitrite, and phosphate levels
are all 0. My pH is 8.0, nitrate is 10, calcium
is 380 to 400 ppm, magnesium is 1200, and
my alkalinity is 12 dKH. I never use carbon.
And as you know, a reef tank is not
complete without some fish. I have a pair of
ocellaris clowns, a tang, and a pair of anthias.
I feed them small portions of frozen brine
shrimp, mysis shrimp, flakes three times
a day, and live brine shrimp three times a
week. I also have several invertebrates: five
Tonga Nassarius snails, two cerith snails,
one Trochus snail, four Turbo snails, two
nerite snails, and ten star snails. I also have a
sea lettuce slug, thirty or more striped micro
Blue-leg hermit crabs Paguristes sp.
brittle stars, and eight blue-leg hermit crabs.
I also have a large variety of stony corals,
some soft corals, and mushroom corals. I
feed these phytoplankton and oyster eggs
twice a week.
Now, my question to you is: How
do I get rid of a mysterious, unknown
encrusted algae that only lives on the
live rock? It is shiny and dark green in
color and looks like turtle weed and
hair algae, but I know that is not what
it is. I’m worried that it will overgrow
and kill my small encrusted sea squirt,
feather duster, fuzzy-tip algae, coralline
algae, and sponges. What would you
recommend I do to get rid of this algae?
Hudson, New York
Interestingly enough, a
similar question appears in
this month’s “Freshwater
Q&A,” but the problem and
its potential solutions will differ between
freshwater and saltwater systems. The slime
is very likely blue-green algae. These types
of algae are actually bacteria, so they can be
killed with antibiotics, such as erythromycin.
However, that would kill the beneficial
bacteria, too. For this reason you would need
to move the live rock to a separate tank if you
go that route, but you could do it a few pieces
at a time.
Activated carbon might actually be good
for removing some of the dissolved organic
compounds that are helping to provide
nutrition for the blue-green algae. Finally,
there are snails that eat this algae. Sea
urchins will eat it too, but then they go to
work on the coralline algae, and you wouldn’t
like that! One scenario would be to remove
the sea urchins once they have taken care of
the green slime, but you need to be sure you
have a place for them (perhaps with another
aquarist with a similar problem).