Fish as Pets | Aquarium, Pond News, Editorials, Reviews

Revised 1/10/19

Unfortunately the use of home water often for Bettas, Angels, and other fish is a widespread practice; despite the simple facts of chemistry that show this is a poor IF NOT dangerous practice for your fish.

There is a BIG difference between water softened naturally found in the Amazon River or in Monsoonal Southeast Asia, compared to the water that comes out of a water softener that uses sodium chloride or potassium chloride.

Overview: I will start by saying most aquarium keepers don't come about thinking they need to go out and get a water softener because of some type of aquarium system they want to keep. This is the rare case.
What usually happens is someone already has a water softener for their home, because of hard water build-up at the house, and decided they want to keep some fish that claim to be from softer water conditions. So then, people then want to know if their home water softener will work for their desired fish. There are differences between these soft water types and this thinking is not in the best interest of the fish.

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What are the differences?

When you use water "artificially" softened by a home/office water softener using sodium chloride or potassium chloride, the resulting water is in simple terms "intolerant" of ANY minerals such as including essential calcium.
The result is no matter how much necessary calcium or other essential elements added to the aquarium, these minerals will be IMMEDIATELY precipitated out of the water!!

The evidence can be found in experiments I have conducted over the years whereby I added a Wonder Shell into water from a home sodium or potassium based water softener. The Wonder Shell dissolved in an unusual manner with a pile of dust around it. As well as, calcium precipitated around the edge of the water line at the top of the aquarium/container.

A bit more detailed explanation of how Water Softeners work:
They do not add salt to your water like many people think, rather water softeners are ion exchange units.
When softwater is mixed with sodium chloride (or potassium chloride) in the salt tank, the solution causes the sodium (or potassium) and the chloride bond to break. Then when the softener regenerates sodium or potassium molecules,they attach to the resin and the chlorides attach to the calcium molecules that are ejected out the drain line.
As water comes in from the city or well, and passes through the resin, the calcium (and other positively charged molecules heavier than sodium) knock the sodium ions off and they attach to the resin in it's place. In the end, you have sodium ions in your soft water, but not sodium chloride (salt). This is where the misconception happens.

With naturally softened water, you would have water from the Amazon River with its minerals come in from the Andes Mountains, that then passes through lower jungles with decaying wood, peat, etc, which slowly leaches tannins into this water.
The result is water whereby the tannins eventually "out compete" with the minerals such as calcium and thus the water becomes "soft" (& more yellow, unlike home softener water).

This can be duplicated with hard well or tap water by "cutting" water with RO (Reverse Osmosis) water or De-ionized water along with adding tannin adding driftwood, pillow moss, Indian almond leaves, etc. to the aquarium.
It is noteworthy that RO water is neutral (to slightly acid) and will except whatever you add to it such as mineral replenishers, UNLIKE home softener water.

A different example is right in my backyard with the Rogue River here in Oregon.
This river begins in Crater Lake National Park where the geography is volcanic, with a lot of acids in the water. Once the river "settles down" in late Spring into Summer, you can see this in the yellow coloration of the water versus more clear rivers such as the Rockies or Sierra Nevada Mountains. As the Rogue River runs downstream toward the ocean, it has many tributaries both small and large that have no volcanic origin, and the water is slowly "charged with more and more minerals, which leads both the GH and KH to rise.

Recommended Product Sources:

What is the importance of this to your aquarium fish?

The simple answer is A LOT!!!

Here are some points about the importance of calcium:

Calcium is a vital component in blood clotting systems and also helps in wound healing.
Calcium helps to control nerve transmission, and release of neurotransmitters.
Calcium is an essential component in the production of enzymes and hormones that regulate digestion, energy, and fat metabolism.
Calcium helps to transport ions (electrically charged particles) across the membrane.
Calcium is essential for muscle contraction.
Calcium assists in maintaining all cells and connective tissues in the body.
Without bio available calcium, many ciclids, especially from South America are very vulnerable to "Hole in the Head" (HITH) Disease.

References:
Aquarium Chemistry; Calcium
Hole in the Head Disease

As well the essential mineral, Magnesium is also driven out by home water softeners. Magnesium is important for proper osmotic functions in fish and invertebrates as well as for Calcium assimilation.

Further Reference: Aquarium Chemistry; Magnesisum

Finally, one of the most important aspects of these essential minerals, which is probably the least understood aspect by many aquarium keepers, is the NEED for a constant supply of positive mineral ions (CATIONS) by ALL fish, even if only in small amounts.
As noted earlier, home water softeners work by attaching calcium and other positively charged molecules heavier than sodium, which means you WILL NOT have these ESSENTIAL mineral ions in your aquarium water!
Without these mineral Cations your Redox Balance will be poor and your fish will be more open to disease.

Reference: Aquarium Redox

Here is a key point from this reference: Aquarium Chemistry; Depletion of Positive Mineral Ions (CATIONS)

Think of it this way; a storage battery "works" only when a positive and a negative electrode are present to maintain an electrical current. When the positive ion charged plates become exhausted, the battery is no longer any good until recharged. In a lead/acid batteries essentially lead (Pb) and lead oxide (PbO2) are changed to lead(II) sulfate (PbSO) in the discharged state (exhausted positive ions), HOWEVER the lead is still present (as with calcium in an aquarium) in a discharged state. The point is to replenish your minerals!

Water changes and additional supplements are generally necessary to replenish these mineral ions (cations). Using the car battery as an example again, when re-charging, a 12 volt battery will show a charge of up to 14 volts in a 12 volt battery shortly after and at the completion of a charge. This is similar to the high GH (often over 400) with the use of many methods of adding mineral electrolytes such as Wonder Shells.

So, if your goal is an Amazon River or SE Asia biotope aquarium and you are trying to create natural soft water. If you use something like I use which areAmerican Aquarium Wonder Shells, I suggest only using 1/4 the normal amount so as to only add some calcium and other minerals, but just enough to boost the mineral Cations so as to improve Redox. Adding the suggest amount can raise GH to high.
As an example; the Large AAP Wonder Shell is the normal dose for a 60 gallon aquarium, however for an Amazon River biotope aquarium I would either use 1/4 of this block or 1/2 of a Medium American Aquarium Wonder Shell.

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