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WATER QUALITY
PARAMETERS
Water is often referred to as the universal solvent, meaning anything
that enters the water will, in some form or another, in some amount or another,
dissolve in that water and affect its chemical makeup. Any gas that is in
contact with the water will also dissolve to some extent in that same water.
Some of these compounds, elements and gases - many different names are used,
depending on how semantically precise one wants to be - that dissolve are
beneficial, and others are toxic and noxious.
The key, therefore, is to ensure that only beneficial ones remain in
solution and that all noxious elements are removed in some way or another.
That is, of course, exactly the purpose of all filtration, and it is also
the reason why the success of a tank really boils down to the relative quality
of the water chemistry. The more efficiently these noxious compounds are
removed, the higher the water quality will be and the better a living environment
for your fish, corals and invertebrates you will be providing.
Water Testing
Does aquarium water really need to be tested? In a word - yes! What should
be tested, and how often, is not as short an answer. In a newly set up aquarium,
water testing is absolutely critical to avoid disaster as ammonia and nitrites
rapidly rise. Even in an established tank, water testing is important to
ensure the health of your fish. Test kits are not that expensive, and should
be considered part of the operating expense associated with keeping an aquarium.
If you cannot afford test kits, or feel uncomfortable testing water yourself,
check with your fish shop to see what they charge for doing water tests.
Some offer one free test each month, or will quote you a flat fee for monthly
testing. Compare their charges against the actual cost of test kits.
Which test kits should you get? Experts will long debate which tests are
necessary. In my experience, the tests I've found most valuable to fish keepers
are Ammonia, pH, Nitrite, and Nitrate. Hardness levels are worth having tested
at least once to establish what your levels are, but don't warrant purchasing
a kit for (unless you have special needs such as a planted tank). Phosphates
are worth testing for if you have algae problems. All testing should be recorded
in a log or journal so you have a record of what is happening over time.
Brown Algae - Diatoms
Diatoms are single celled algae, brownish in color.
The cause: excess nutrients, silicate and silicic acid are the ingredients
for a diatom bloom. Silicic acid enters the aquarium by using tap water;
substrate can contain silicates that leach out over time. RO/DI units can
filter silicic acid out, but only for a limited time. Eliminating silicates
can control diatoms.
ALGAE
are indicators
for lacking water maintenance
It has unequivocally been proven that an infestation of algae will only
occur if there is a specific nutrient deficiency, wrong lighting being applied
or inadequate chemical water conditions being dominant in the aquarium. Also,
an over-supply of nitrogen, especially in nitrate form, encourages algae
because natural biotopes never reach such high nitrate values as can often
occur in aquariums.
It is therefore entirely appropriate to formulate the basic principle
that algae in an aquarium are an indicator that all is not right within the
aquarium system. This can already be recognised by the fact that algae prefer
to settle on sick or withered plant segments.
Dealing With Phosphates in
A Reef Aquarium:
Sources of Phosphates
Somehow, even though we may not be aware of it, the phosphate levels
dissolved in our aquarium water have a tendency to rise unless, of course,
we do something about their presence. This is especially true when an aquarium
has not yet aged for a long enough period of time. It also happens in aquariums
that are not operated using the more recent reef aquarium principles.
1.3.5 Phosphate (PO4)
Phosphates, along with nitrates, are a primary nutrient of algae. Tanks
with "high" levels of phosphates tend to be infested with hair algae. All
authors cite zero ppm PO4 as a good goal. An upper level 0.1 ppm is recommended
by Tullock (1991) with less than 0.05 ppm given by Thiel (1991).
The use of kalkwasser has been closely tied with reduction in phosphate
levels. This may be due to precipitation of the phosphates at the kalkwasser
injection site, or, more likely, due to increased export via skimming due
to the associated higher system pH.
Also you can eliminate phosphates by using
a Reverse Osmosis filter.
By not using such principles I mean that the aquarium is either a fish-only
tank with dead coral in it, or it is a reef tank that does not use the live
sand and/or the liver rock method of filtration.
Phosphate
Phosphates enter the aquarium mostly through water changes using tap
water, but also through food and leaching carbon. Next to chlorine some
communities also add phosphates to the tap water. Dying plants and algae
will create phosphates while decaying (mineralization).
Very interesting to know, is that the high pH level required for salt
water will hold phosphates in an insoluble stage. A drop in pH, and this
happens in a matter of days, will make those compounds water soluble and
therefore available to the algae spores.
Please note, that the pH levels slightly vary within the tank, and a
drop in one spot can have an effect.
Also you can eliminate phosphates by using
a Reverse Osmosis filter.
Water Parameters and What They Mean
Basic's and more things you should know or at least have access to!
Testing and what it means to the hobbyist
Water Testing
Water chemistry is not visible; therefore it is vital to check it on a
regular basis. The best way to make this a routine is to check on the tank
chemistry while changing the water.
The vital parameters are pH, nitrates, nitrites, and carbonate hardness
(salinity of course for marine tanks).
pH in the range of 6.5 – 7.5 is suitable for most species, as they
can adjust if slightly out of range. Stability is the main factor with pH.
KH (carbonate hardness) is the indicator of pH stability. It should be
kept under close observation if it comes close to 4.5 dH (degree hardness)
or 80 ppm. You must take action if it decreases any further.
Half a teaspoon of baking soda per 25 Gallons will raise the kH by about
1 dH (17.8 ppm).
Nitrites should be undetectable at all times (except during cycling).
If you detect nitrites make sure you check on ammonia as well.
Nitrates should be kept below 10 ppm in freshwater and 5 ppm in marine
and reef (preferably 0 ppm).
Recommended Reef Tank Parameters
-Calcium...................380 to 450 mg/L
-Magnesium.........1000 to 1320 mg/L
-Alkalinity........................8 to 11 dKH
-Ammonia..........................< .2 mg/L
-Nitrites..............................< .2 mg/L
-Nitrates.............................< 10 mg/L
-Phosphates........................<.03 mg/L
-Specific Gravity.............1.022 - 1.024
-Water Temp..........................78f to 80f
-Water Flow > 5 times tank volume per hour
TEST KITS
TEST KITS
Generally, five water parameters concern the hobbyist. The levels of
ammonia, nitrite, and nitrate present, the water hardness and pH. (Refer
to the Water Chemistry Section to find out why these are important). As test
kits are invariably expensive items possibly due to the chemicals contained
within them or to the accuracy to which modern kits measure. It may therefore
be prudent to think why you need to test the water and what to test.
Some fish keepers never seem to have problems. Their aquariums are crystal
clear, the fish are healthy and their plants are flourishing. These aquarists
have experience. They know how often (and how well) to clean their filters,
they know exactly how much water to change and how often - they have learned
to manage their aquarium system. Guaranteed they did not learn this overnight
or without making mistakes themselves. Undoubtedly, the majority of advanced
fish keepers will have used a test kit to help assess tank conditions and
diagnose problems at some point.
Water Chemistry
There are two approaches to water chemistry; one can keep fish suited
to the local tap water and we recommend this option to beginners - your local
retailer should be able to advise you which species are "hardy". Alternatively,
one can modify the water's chemistry but be aware, modifying the water can
be expensive, time consuming and there is always the possibility of error.
Learn about water hardness, pH, gH and kH here!
As fish keepers, we are told that it is important to measure the pH, kH
and gH of our aquariums and source water. Fish suitability is commonly defined
in terms of the pH and gH of their natural habitat. Many aquarists, even
though they measure these parameters, don't completely understand them, know
how they can interact, or the affect they may have on fish. The purpose of
this article is to try and provide some definition and clarity to the terms,
determine how they interact as well as their affects upon aquarium fish.
NITROGEN CYCLE
THE AQUARIUM NITROGEN
CYCLE
In the natural environment, large bodies of water
provide the cleansing action necessary to disperse the waste substances produced
by fish. In the closed confines of an aquarium, fish depend on the aquarist
to provide an efficient system to purify water. Biological filtration is
a natural means of removing toxic ammonia based wastes from the aquarium.
The establishment of a well balanced nitrogen cycle is paramount for the
health and success of any aquarium.
The
Nitrogen Cycle
"nitrosomonas bacteria"
The most important life in your aquarium!
CLOUDY WATER
Nobody likes cloudy water: not the aquarist, certainly not his/her spouse,
and absolutely not the fish! Cloudiness is not only an unsightly but an unhealthy
condition for the aquarium, as huge numbers of microscopic bacteria and algae
use up precious oxygen.
When your aquarium's water is cloudy and grey colored, it means that you
have a bacterial bloom in your tank.
Setting up an aquarium at home can be fun and rewarding. Home aquariums
are miniature ecosystems and the interactions of living organisms are essential.
Keeping an aquarium "balanced" is the key ingredient for success.
We can help!!
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Water Parameters and Your AQUARIUM
pH - Nitrogen Compounds - Phosphate - Silicate - Chlorine/Chloramine
Water Hardness
General Hardness (GH)
GH primarily measures calcium and magnesium ions. It is important for
breeders (some species require very soft water, which is hard to maintain,
requiring constant monitoring for maximum success). Other then choosing the
right fish for the existing conditions, the GH is not all that important
for the average hobbyist.
Common measurements use ppm and the equivalent mg/l. The conversion of
degrees into ppm and mg/l is by multiplication of 17.8 or vice versa.
Carbonate Hardness (KH)
KH measures dissolved bicarbonate and carbonate ions. They are commonly
referred to as the buffering capacity. KH determines on how stable your pH
will be and is therefore very important.
Picture this: carbonate ions bond with hydrogen ions (which is your pH).
The more bonding the higher the pH. Lesser carbonate ions results in a drop
of pH.
KH of 70 ppm and less, will initiate the pH crash.
Baking soda is known to increase KH and distilled water to decrease KH
(as distilled water has a KH of 0).
We do not encourage attempting adjustments of these values unless it
is absolutely necessary. Should you feel the need to make adjustments, please
be cautious and take it slow. Be sure to carefully monitor any changes in
KH and pH. If your fish and tank are thriving, it is not recommended any
adjustments be attempted.
pH
pH is the measurement of hydrogen ions. Increased hydrogen ions (less
bonding) result in a drop of the pH (more acidic water), while a decrease
results in a pH rise.
pH = power of hydrogen.
pH is measured on a scale from 0-14. The neutral value is 7, while values
below are more acidic (towards a car battery) and values above 7 more basic
(towards dish soap).
Changes in pH are a common cause of fish fatalities. Fish can adapt to
most pH levels, if not broadly out of range, but they can’t adapt to
bouncing values.
This is because pH has a logarithmic function (mathematical - meaning
ten-fold). In other words, a change in pH from 7 to 6 means 10 times more
acidic water. A further drop to a pH of 5 equals 100 times more acidic
water.
If you have to adjust the pH in your tank, always consider the carbonate
hardness. The pH in harder water more difficult to adjust because it bounces
back, while softer water is more easily adjusted. Keep in mind to change
it slowly as it causes a lot of stress to your fish. Maintaining a stable
pH is generally more the way to go.
Some other facts about pH:
>>>Ammonia increases in toxicity with rising pH
>>>Nitrifying bacteria experience a growth and action reduction
starting at a pH value of 6 and lower
Nitrogen Compounds
Ammonia, Nitrite, Nitrate are well described on our site.
Phosphate
Phosphates enter the aquarium mostly through water changes using tap
water, but also through food and leaching carbon. Next to chlorine some
communities also add phosphates to the tap water. Dying plants and algae
will create phosphates while decaying (mineralization).
Very interesting to know, is that the high pH level required for salt
water will hold phosphates in an insoluble stage. A drop in pH, and this
happens in a matter of days, will make those compounds water soluble and
therefore available to the algae spores.
Please note, that the pH levels slightly vary within the tank, and a
drop in one spot can have an effect.
Silicate
The most common points of entry are the substrate, salt, water and dying
diatom algae. Please keep in mind, that R/O and D.I units (filters to purify
tap water by membranes or by chemical/ mechanical processes creating distilled
water) will prevent silicates only for a few days, before they find the way
through the membranes.
Another form of silicates is silicid acid, created by decaying organic
matter. Same as phosphates, they can be water insoluble at a high pH, and
become readily available with decreasing pH levels.
Chlorine/ Chloramine
Water companies add chlorine or chloramine as a disinfectant to tap water.
Chlorine is less stable then chloramine and airs out in just a few days.
Some hobbyists simply let the water age for a couple of days before doing
the water change, thus airing out the chlorine.
Chloramine is much more stable. That is why communities switch from chlorine.
As it is very stable, it does not air out even if heavily aerated.
Chloramine, a mixture of ammonia and chlorine, passes (unlike chlorine)
through the fish’s tissue directly into the bloodstream. In the blood,
just like nitrite, it destroys the oxygen carrying cells. Chloramine can
cause all fish to die within 24 hours.
Comments
Carbonate hardness, pH, nitrate, and ammonia/nitrite (salinity for marine
tanks), should be tested on a weekly basis. Also be sure to test the water
used during water changes.
The water parameters and definitions in this issue are intended to help
you understand the conditions in your aquarium. A healthy aquarium requires
immediate attention should one of these parameters produce dangers
readings.
Other parameters such as trace elements i.e. iron, copper, calcium etc.
should be checked on, if you add them in some way (as supplement or
fertilizer).
Depending on the set up (marine/reef/plants), other factors come in to
play, such as dissolved oxygen, redox potential or CO2. These topics will
be covered in future issues regarding specific tank types.
Water and Water Quality
Natural Seawater
Water Parameters
Synthetic Seawater
Marine organisms are directly affected by the chemical, biological, and
physical characteristics of their environment. The water around coral reef
habitats is chemically stable because of the large volume of water around
it, the constant currents, wind, maintain stability of the water. As a result
the reef animals are not subjected to a wide range of fluctuations in the
water. When there is a change it is of short duration and the animals are
not adversely effected. The situation in an aquarium are totaly different.
The water in the aquarium is not subjected to constant renewal as it is in
the ocean. It is just the opposite the aquarium is subjected to extensive
alterations after the introduction of marine organisms. The alteration of
the water is due to the buildup of chemicals that come from various biological
processes most commonly the metabolic activities of the fish. If these chemicals
continue to buildup to concentrations beyond what the marine animals can
tolerate, the lives of the animals can perish. The toxicity of some of these
chemicals is lethal in low concentrations , so regular testing of the aquarium
water and periodic water changes is very important in maintaining water quality
within acceptable parameters.
Activated Carbon
in the Filter
Aquarium Filtration
The proper function of the filter is essential. Filter inserts (floss/
cartridges/ carbon) should be exchanged at least every 4 weeks. Trapped particles
will decompose in the filter as they would in the tank. A high fish load
may require shorter periods, to avoid problems. The filter should also be
cleaned once a month (do not touch the bio-wheels if present) by using the
water extracted from the tank during the water change.
Recommended Aquarium Maintenance Routine
Daily
Make sure the equipment is running properly.
Watch your fish during feeding. Behavioral changes are a good indicator
of a potential problem.
Weekly
Count your fish. In case of fish death, smaller species can decompose
quickly, resulting in ammonia and/or nitrite spikes and eventually high nitrate
levels.
Every Other Week
Test your water for the vital parameters: pH, carbonate hardness, nitrite
and nitrate. Try the MultiStick for fast and accurate testing.
Change 10-15% of the water.
Vacuum the gravel.
Clean the aquarium walls. Filter floss is fairly cheap and very efficient.
Start from the bottom upward and rinse out often. (This technique will minimize
the amount of algae spores remaining in the water).
Rinse filter inserts (cartridges) with the extracted water.
Monthly
Replace filter inserts, cartridges, floss, carbone.
Inspect tubing, connections, airstones, skimmers and other parts for proper
operation.
Clean aquarium top to assure your lighting is not affected.
Check the expiration dates printed on the boxes and bottles of the aquarium
supplies you use. Do not use after the imprinted date (especially test kits).
They will give false readings and may prompt you to take unnecessary action.
Most public water supplies
have contaminants well below the EPA levels and
some reef tanks have done fine on some public supplies. In general, however,
it is recommended that some form of post processing be performed on public
water before it is introduced into the reef tank.
Although some people have access to distilled, de-ionized or reverse osmosis
water from public sources, most will use a home sized system to produce their
tank water. The two most common systems used are de-ionization resins, and
reverse osmosis membranes.
Marine Lab
This master marine aquarium test kit includes the following Mini Labs:
pH/Alkalinity, Ammonia, Nitrite, and Nitrate.
Water chemistry/aeration
As the biological processes within an aquarium take place, fish and nitrifying
bacteria utilise oxygen and waste gases such as carbon dioxide and nitrogen
are produced. If an imbalance of harmful gasses occurs, and the oxygen content
in the water becomes deficient, the fish will literally suffocate. An indication
of this happening is when fish hang just below the water surface and gulp
air directly from the atmosphere. (Note: some fish such as labyrinth fish
and Corydoras sp. will occasionally take air from the surface naturally).
In an aquarium, the only place that an exchange of gases can occur is
where water is in direct contact with the atmosphere. It is therefore important
to maximise the surface area of the water.
Tall tanks may not have a large enough surface area to provide an adequate
oxygen interchange and in heavily stocked aquariums the demand for oxygen
by the fish may exceed the supply at the surface. In very warm tanks oxygen
diffuses rapidly from the water and additional agitation of the water surface
will be required to maximise the surface area available for the exchange
of gases.
Normally the return from a filter agitates and circulates the water enough
to promote sufficient diffusion of gasses in and out of the water and additional
aeration is not necessary. To address any additional aeration requirements,
an airpump is sometimes employed. The stream of pretty bubbles which it produces,
via an air stone, is often mistakenly thought to somehow inject air into
the water but in fact an airpump actually provides aeration by circulating
and disturbing the water surface to create a larger area for oxygen exchange.
Too much turbulence at the water surface may drive off carbonic acid, which
is an important plant fertilizer or cause too great a current for the fish.
It is for these reasons that airpumps and filters are available in a range
of sizes or have flow regulators to tailor their output to the tanks needs.
An airpump’s primary role is to provide additional
circulation and to disturb the water surface creating a larger area for oxygen
exchange as described in the aeration section, (not to mystically force air
into the water as is often thought) but this is not the limit to their use.
(About)
Aquarium pH & Alkalinity Simplified
The pH (power of Hydrogen) level in a saltwater aquarium is a constant
concern to most aquarists. Whereas the occupants in a FO (Fish Only) tank
can tolerate a fairly wide range of pH levels for periods of time with no
major harm, the occupants of a reef tank rely heavily on a constant pH level
in the right range to just survive, let alone thrive.
In order to control/adjust pH, we must first understand what pH is. pH
is simply a measurement of the acidity/alkalinity of a solution. A ph of
7 is considered to be "neutral", neither acid or alkaline. pH levels above
7 are considered to be alkaline or "base". pH levels below 7 are considered
to be acidic. In order to keep this discussion fairly basic, we won't get
into the interactions of ions on a chemical level that make it all happen.
We will just stick with what happens on a layman's level. If you are of a
mind for a more scientific explanation, you can read John H. Tullock's, Water
Chemistry: pH and Alkalinity article.
The generally accepted pH level in a saltwater aquarium is between 7.6
and 8.4. Reef tanks are a bit more sensitive to pH and should be kept more
toward the higher level.
The normal trend for pH in a tank is downward, or more acidic. The additions
of acids into a tank will lower the pH in the tank water. These acids come
from several sources, the primary ones being: (1) excess carbon dioxide (CO2)
from respiration caused by lack of sufficient gas exchange, (2) nitric acid
from biological filtration (nitrification), and (3) organic acids from metabolic
wastes. Respiration and metabolic wastes are a natural part of the ocean.
The reason that sea water pH does not change is that sea water contains a
number of chemicals, such as bicarbonate, calcium, carbonate, borate, hydroxide
which act as natural "buffers" that retard the drop in pH.
The degree to which a solution maintains its pH when acid is added is
termed the "alkalinity" of the solution. Related terms used in reference
to aquariums are "carbonate or calcium hardness", and its German equivalent,
"KH or dKH". The amount of "buffers" in sea water determines the
alkalinity.
When the pH in a tank starts to drop, it is an indication that the buffers
are getting worn out. There are a few things that you can do to remedy this
increase in acidity. You can use the "quick fix" by adding bicarbonate of
soda (baking soda), or use any one of a number of commercial pH buffering
products available on the market.
The generally accepted "tried and true" method for stabilizing pH is
still performing a partial water change in your tank. This not only refreshes
the natural buffers, but also restores the trace minerals in your tank water.
Of course, reducing the causes of the drop in pH is always wise. Removing
all uneaten food and fish detritus from the tank on a regular basis will
go a long way toward retarding the pH drop.
If you want to get into a more constant and automated (and a bit more
complicated) method of maintaining your pH levels, along with adding the
constant supply of calcium needed to maintain a reef tank, you can graduate
to dosing methods or using a calcium reactor. To learn more about adding
or dosing with calcium (a.ka. limewater or kalkwasser), as well as how it
relates to pH, alkalinity and KH, refer to the Aquarium Care Resources
Index.
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