Page 224 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

222 MARINE FISH: MAINTENANCE

that the nitrogen cycle is working well, the water is relatively
Heat from the lighting pure, and oxygenation is good. The redox potential naturally
causes evaporation
from the water’s surface fluctuates over any 24-hour period, due to the biological
processes taking place in the tank, so take readings at the same
time each day. A sharp decline may signify that the airstone is
Before you add replacement water,
make sure it is at the same blocked. Live rock and some types of algae help to raise the
temperature as the water in the tank redox potential; however, if the redox figure exceeds 400 mV,
which can happen if your ozonizer (see p.211) is too large for the
Evaporation of tank water is aquarium, there may be fatalities among the tank occupants.
the main cause of changes in
salinity. As water evaporates, the
concentration of salt in the tank
(and thus the SG figure) rises. To
replace lost water and restore the NEW TANK SYNDROME
correct salinity, top off the tank
with fresh, dechlorinated water; Ammonia and nitrite can rise to dangerous levels in a new tank,
do not use salt solution, which before the colonies of beneficial bacteria that break down these
will make the problem worse. toxic waste products have developed in the biological filter. Use test
kits to take weekly readings of ammonia and nitrite in a new tank
to monitor the progress of this maturation process. Some hardy
You should also test the concentrations of trace elements, species, notably damselfish (see pp.240–243), can be introduced at
especially in a reef tank. Calcium, strontium, iron, and iodine this time, but most marine species should be added to the
are vital for a healthy reef community. The ideal levels are aquarium only when the system has stabilized.
400–475 mg/l for calcium, 8 mg/l for strontium, 0.05 mg/l
11
for iron, and 0.5 mg/l for iodine. You can correct these levels 10 The filtration system
in a new tank is likely
by adding commercial aquarium preparations. Phosphate, too, 9 Nitrite to take at least two
is essential, but if it exceeds 0.01 mg/l, it can lead to a months to become
mature, with peaks of
proliferation of unwanted hair algae (Derbesia sp.). Level (mg/liter) 8 7 6 Ammonia ammonia and nitrite
occurring initially,
Redox meters 5 4 followed by a gradual
rise in nitrate.
An excellent way of monitoring the general health of the tank is 3 2
to install a redox meter, which measures the water’s oxidation- 1 Nitrate
reduction potential—that is, the ease with which chemical 0
20
24
reactions occur in the water. The reading, in millivolts (mV), 0 4 8 12 16 Time (days) 28 32 36 40 44 48
should ideally lie within the range of 320–380 mV, indicating Introduce Other fish can
damselfish be introduced
to the tank to the tank
A collection of marine fish, such as the damsels, angelfish, and tangs in
this tank, can only be built up safely over the course of many weeks.

VACATION ISSUES
• Try not to be away when
a tank is in the early stages
of maturing or immediately
after adding new occupants
to an existing setup.
• Carry out a partial water
change a few days before you
leave, to ensure all is well.
• Leave very clear feeding
instructions, in writing.
• Be sure to leave sufficient
food and a replacement
lighting tube or bulb.

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