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Water Temperature, Chemistry and Flow
Generally speaking, our goal is to manage in a relatively
small closed system, a stable environment that mimics the
natural environment (a very large, open system) of the animals
and plants we are keeping -- think, Great Barrier Reef. Note
though that wide variations
appear to all "work" successfully.
Start
fresh:
In the
absence of safe and reliable natural saltwater (NSW), we have to
make our own. Because most tap water has all kinds of
"stuff" harmful to a closed saltwater reef system, we start with
pure fresh water and build from there.
The most popular approach is to use an RO or RO/DI system to
make pure freshwater in a food grade plastic container.
Then, add-in a commercial mix to get the desired saltwater with
the required
chemical components.
We use this artificial saltwater (ASW) to start the system and
for periodic water changes.
Temperature:
80°F (if we
had to pick one)
Acceptable range: 72-84°F
The debate continues. Note that there are videos online of delicate (so "they"
say) acros totally out of the water at low tide on a daily basis
baking in the mid-day sun. Doesn't sound so stable to us.
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Water Movement and
Flow:
General rule is a minimum of 10x your tank volume per hour.
For high flow animals like SPS corals, consider up to
20x.
The water needs to be moving within the display tank, and
through the sump (the water treatment and filtration area) and
back again. How, when, where, and how much depends somewhat on
the animals. 3-5 times your display volume per hour through your
sump is more than sufficient for filtration purposes.
Flow and movement can be achieved from a combination of
the return pump and devices (pumps, wavemakers,
propellers) placed directly in the display tank.
On a natural reef, there is a gentle flow around the coral head
every two to three seconds. Every 10 seconds there is a second
much stronger surge. Lastly, tidal flow moves unidirectionally
twice a day.
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Chemistry:
Debates here also.
Salinity
FOWLR: 1.020
Reef: 1.025
pH
subject to change between collection and testing; can be done
accurately and inexpensively at home
FOWLR: 7.6 to 8.4
REEF: 8.0 to 8.4
Ammonia (NH3-4)
Natural Seawater Value: 0.010 mg/L
Acceptable Range: 0.000 to 0.050 mg/L
Nitrite (NO2)
Natural Seawater Value: 0.010 mg/L
Acceptable Range: 0.000 to 0.100 mg/L
Nitrate (NO3)
Natural Seawater Value: 0.050 mg/L
Acceptable Range: 0.000 to 25 mg/L
Phosphate (PO4)
Natural Seawater Value: 0.030 mg/L
Acceptable Range: 0.000 to 0.250 mg/L
Silica (SiO2-3)
Natural Seawater Value: 0.040 mg/L
Acceptable Range: 0.000 to 0.500 mg/L
Potassium (K)
Natural Seawater Value: 390 mg/L
Acceptable Range: 350 to 450 mg/L
Calcium (Ca)
Natural Seawater Value: 400 mg/L
Acceptable Range: 350 to 450 mg/L
Boron (B)
Natural Seawater Value: 4.6 mg/L
Acceptable Range: 3.0 – 6.0 mg/L
Molybdenum (Mo)
Natural Seawater Value: 0.01 mg/L
Acceptable Range: 0.0 to 0.12 mg/L
Strontium (Sr)
Natural Seawater Value: 8.1 mg/L
Acceptable Range: 5.0 to 12.0 mg/L
Magnesium (Mg)
Natural Seawater Value: 1280 mg/L
Acceptable Range: 1100 to 1400 mg/L
Iodine
(I¯)
Natural Seawater Value: 0.060 mg/L
Acceptable Range: 0.030 to 0.090 mg/L
Copper (Cu++)
Natural Seawater Value: 0.030 mg/L
Acceptable Range: 0.000 to 0.030 mg/L
Alkalinity (meq/L)
Natural Seawater Value: 2.5 meq/L
Acceptable Range: 2.5 to 5.0 meq/L
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