The Importance of Calcium, Kh, and Magnesium in Aquariums

Many aquarists overlook the need for calcium,which is generally kept at a pH below 6.5. I have
electrolytes, magnesium and the effect of asuccessfully used calcium (Wonder Shells or
proper KH (Carbonate hardness) in theirCalcium Polygluconate) in discus aquariums by
freshwater aquarium. KH is basically the bufferingusing a mix of RO (Reverse Osmosis) water and
capacity of your aquarium, a Kh above 80 ppmtap water (dilution will vary depending on your tap
helps prevent sudden drops in ph (You canand tank water parameters). I then add
convert dH [German hardness] ppm by multiplyingelectrolytes to the RO water and add peat to the
your dH by 17.9). This is especially important withfilters. I have used this method successfully with
livebearers, goldfish, African cichlids, brackish anddiscus and added the needed calcium with no pH
many other freshwater fish. The production ofclimb.
Nitrates (nitric acid) will slowly reduce your ph, butOther needs for calcium:
a proper KH will keep a more stable ph. This is• Calcium is a vital component in blood clotting
important to note, if your KH is low and your phsystems and also helps in wound healing.
has been dropping, a large water change (don't• Calcium helps to control nerve transmission,
get me wrong, water changes are VERYand release of neurotransmitters.
important) can cause stress on your fish, or even• Calcium is an essential component in the
kill them.production of enzymes and hormones that
KHregulate digestion, energy, and fat metabolism.
Another consideration of KH is that you can• Calcium helps to transport ions (electrically
generally safely add the buffers (both freshwatercharged particles) across the membrane.
and saltwater) that effect KH without sudden• Calcium is essential for muscle contraction.
changes in chemistry (unless your KH is under 80• Calcium assists in maintaining all cells and
ppm already), unlike a direct ph or GH change. Forconnective tissues in the body.
this reason you do not always have to checkOther needs for Magnesium:
your KH before adding buffers such as Wonder• Normal calcium balance in organs
shells.• Healthy muscles
Baking Soda (Sodium Bi-Carbonate HCO3-), is• Healthy nerve transduction
often used for KH, Sodium Bi-Carbonate will• Healthy calcium balance in blood vessels
buffer at 8.0 to 8.2. They are very good atELECTROLYTES;
buffering at that pH. Just a little carbonate willElectrolytes are molecular substances containing
absorb free H+ ions, and this causes alkalinityfree ions which behave as an electrically
(which is the lack of H+ ions). To stop theconductive medium. In fish (or other living things)
carbonate ions from consuming too much H+ andthe primary ions of electrolytes are sodium (Na+),
to keep a pH of 7.0 we need to restrict thepotassium (K+), calcium (Ca++), magnesium
amount of Baking Soda used, as it is always(Mg++), chloride (Cl-), phosphate (PO4---), and
looking for H+ ions to consume. This is why Ihydrogen carbonate (HCO3-).
prefer using Calcium based products, WonderFish and other aquatic life forms require a subtle
Shells being my first choice, aragonite my second.and complex electrolyte balance between the
Back to baking soda, this is an old stand byintracellular (inside the cell) and extra cellular
method based on the fact that baking soda does(outside the cell such as plasma membranes)
raise pH and kH, the problem is there is muchenvironment. In particular, the maintenance of
new research to show that calcium, magnesium,precise osmotic gradients of electrolytes is
electrolytes and Redox play a more importantimportant. These gradients affect and regulate
role in aquatic chemistry than just pH or basic kHthe hydration of the fish, blood pH, and disease
alone. Unfortunately the aquatics hobby is full ofresistance and are important for proper nerve
aquarist (especially in forums or uninformed LFS)and muscle function.
that regurgitate this old information withoutSalt is commonly used in a dose of one
checking the facts.tablespoon per 5 gallons (20 liters) in freshwater
A proper KH can also have a positive effect onaquariums. This is one way to add some
the aquarium Redox Potential, which recentelectrolytes, but this should not be the only
studies have shown to be more important to fish(Wonder Shells add many other electrolytes). Salt
and other animal health than pH. Proper electrolytealso will aid in disease prevention as it will help with
balance contributes to the Redox reductionthe generation of the slime coat (or Mucous) on
potential of water, maintaining a more stablefish as salt acts on the osmotic gradient. But care
water environment, better clarity and the excessneeds to be given with salt sensitive fish such as
electrons attach themselves to free radicals,catfish not to exceed this amount. Another
improving disease resistance.aspect of salt is that although it aids in the
If you have a very unstable KH level (dropsprevention and even treatment of Freshwater Ich
rapidly), look into causes such as a large amount(Ichthyophthirius multifilis), it is poor treatment for
of decomposing organic material. The morea full blown infection despite many anecdotal
organic break down (de-nitrification), the morecomments by many.
acids produced. Some filters if not cleanedFor MUCH more on the effects of electrolytes
regularly can cause this; including canister, UGF,and their funtions in freshwater and saltwater:
and Wet/Dry.How do Fish Drink; Proper Osmotic Function
GHFACTS ABOUT ELECTROLYTES AND CALCIUM;
General hardness (GH) refers to the dissolved* All fish require calcium and electrolytes, including
concentration primarily of magnesium and otherdiscus, bettas, tetras and other soft water fish. In
mineral ions. Both Calcium and magnesium arefact the lack of electrolytes and calcium is a
important for proper internal osmotic processes inmajor problem for poor health in bettas and
fish (and invertebrates). Other ions can contributediscus.
to water hardness but are usually insignificant and* It is possible to have adequate calcium and
difficult to measure. When fish are said to preferelectrolytes without raising pH to a harmful level
``soft'' or ``hard'' water, it is GH, not the kH that isfor discus, bettas and other fish that generally
being referred to. GH will not directly affect pHprefer low pH water (many discus breeders in LA
although "hard" water is generally alkaline due tokeep there discus pH higher than in the wild
some interaction of GH and kH. A high GH inanyway).
freshwater can cause respiration problems in fish,Wonder Shells:
for a general freshwater aquarium a GH betweenA product called a “Wonder Shell” will help
50-100 ppm is best (lower for Discus, higher forwith your calcium, magnesium, and Kh of your
mollies/ African Cichlids).aquarium. I prefer them over crushed coral, as
Magnesium is important in SMALL quantities forfrom my experience, the calcium contained in
proper osmotic functions in fish.crushed coral does not dissolve rapidly enough (I
Magnesium is better added in the proper balancehave seen African cichlid aquariums with 2+" of
with calcium (which both are essential to eachcrushed coral drop in ph from 8.2 to 7.4 and even
other for proper utilization), in such products assome marine, without adequate water changes).
Wonder Shells or aragonite sand in a small bag inWonder Shells also come in a medicated version
the filter (although the later is not as reliable).for control of aquarium ich and fungus.
CALCIUM CARBONATE:Here are a few of their attributes:
Calcium carbonate in your aquarium will keep a* Helps keep aquarium clear
more stable Kh, while magnesium is another* Maintains stable ph
important element that works with calcium. A* Adds necessary minerals (electrolytes)
proper amount of Calcium and Magnesium in your* Removes chlorine
aquarium will affect the fish’ health positively.* Great for Goldfish, livebearers, cichlids, and
Besides helping to keep a stable Kh, magnesiummore
and calcium have been shown to increase* Contains Calcium carbonate; sodium thiosulfate;
resistance to degenerate diseases by lowering themajor, minor, and trace elements including
acidity in the body. This will help with preventionmagnesium sulfate. Magnesium and calcium been
of ich, fungus, and general “wear andproven to help fish (and humans) during stress
tear” in your fish. Calcium also helps in healingand to help prevent disease due to acid buildup in
and stress, and without proper calcium levelsthe body.
healing may be difficult or impossible. The additionFor more aquarium information and a picture of
of antibiotics (such as Tetracycline) will lowerthe pH scale see our full article below:
calcium absorption.Calcium, KH, and Magnesium in Aquariums; How to
Another note about calcium; Calcium is verymaintain a Proper KH, why calcium and
important to proper discus health, yet calcium canelectrolytes are important.
adversely affect the pH of a discus aquarium,