Page 223 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

MONITORING AND ADJUSTING 221

CHANGING THE WATER
Partial water changes not only reduce harmful
accumulations of nitrate, phosphate, and
other chemicals by dilution but also replenish
levels of carbonate (reinforcing the buffering
capacity) and trace elements, which are vital
to the well-being of the tank occupants.
When setting up the aquarium, make an
inconspicuous mark on the side of the tank
with a felt-tip pen to show the water level 2 Check the salinity and temperature 2 Drain the water and clean the gravel
2
1
when the tank is full. This makes it easier A conductivity meter gives readings in Fix a gravel cleaner to the siphon and suck
to fill up the tank with the correct amount millisiemens per centimeter (mS/cm). At up mulm from the substrate while draining
of water, both when making partial water 77°F (25°C), 50.1 mS/cm corresponds to the water. This will prevent the undergravel
changes and when replacing evaporated water. an SG reading on a hydrometer of 1.023. filter from becoming clogged with waste.

CHECKING SALINITY
The correct salinity, in terms of specific
gravity (SG), will be in the range of
SG 1.020–1.025, depending on the species
in your tank. Salinity can be tested with
a hydrometer (see p.215) or a conductivity
meter, which determines the water’s salt
content from its ability to conduct
electricity. With a hydrometer, you may
need to adjust the reading to take account
of the water temperature: cold water is
2 Add more water 2 Clean out the protein skimmer denser than warm water, so it gives a
3
4
Replace the drained water with a fresh, Carefully remove the accumulated debris slightly lower SG reading. The instructions
dechlorinated salt solution of the correct from the cup. Then rinse the cup with warm, provided with the hydrometer should
temperature and salinity. Test the water for dechlorinated water to remove fat deposits, enable you to make the right adjustments.
toxic copper before adding it to the tank. which make the skimmer less efficient.

The calcareous substrate bolsters buffering because it contains
calcium carbonate, which gradually dissolves and replenishes the
TESTING THE WATER water’s carbonate content. The typical pH range is 8.0–8.3,
Tank samples can be tested with reagents to monitor a range of but pH inevitably falls as carbonate is used up. A carbonate
water parameters, including pH and levels of chemicals such as iron, hardness test (also called an alkalinity test) measures the level
nitrate, phosphate, carbonate, calcium, strontium, iodine, and copper.
Read the instructions on the kits carefully, store them appropriately, of carbonate in milliequivalents per liter (meq/l). If the result
and use them before they are out is outside of the range of 3.0–3.5 meq/l, take remedial action;
of date; otherwise, they will give partial changes of gravel and water help to restore the buffering
inaccurate readings that may capacity, as does the addition of a commercial buffering solution.
endanger the health of both fish
and invertebrates. Electronic In an established tank with good filtration, there should be
meters give more accurate results no ammonia or nitrite. The nitrite level increases slightly if you
for many of these parameters, but add new fish or invertebrates, reflecting extra waste output,
they are far more expensive.
but it soon falls as the nitrogen cycle (see p.34) converts nitrite
Test kits use reagents that cause the into nitrate. Use partial water changes to reduce nitrate levels—
water sample to change color. The which should be close to zero and never above 20 milligrams
sample is then compared to a color
chart that gives the numerical figure. per liter (mg/l)—preferably in conjunction with a protein
skimmer (see p.211) to remove waste before it decomposes.

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