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Hi All...

I've just had my tank water tested by my LFS, who tell me it needs to be hardened... I test it at 2.2 degrees KH..

Does anyone know if the Hardness levels expressed here on FishProfiles.com (in the actual profiles) are in KH or GH? I guess 2.2 dKH is probably a little low, and so I'm working on hardening it slightly, but I want to be sure what I'm working with. :-)

Hi,
Boy thats a head scratcher... how can water be hard?
Unless you belly flop on it from the spring board or
off your skis at 35 mph!

Hardness is measured in Parts Per Million (ppm) or in
German Degrees of Hardness(GDH, commonly refered to as
simply "degrees".

There are two "types" of hardness:

General Hardness (GH) is a measurement of all the minerals
dissolved in the water. Primarely these are the
Calcium (Ca2+) ions and the Magnesium (Mg2+)ions.

Carbonate Hardness (KH) is a measure of the carbonate
(CO3^2) and bicarbonate (HCO3)ions in the water.

There are four general ranges of hardness:

Soft Water that tests between 0-3 Dgh (0-50ppm)
Medium Soft Water that tests between 3-6 Dgh (50-100ppm)
Medium Hard water that tests between 6-11 Dgh (100-200ppm)
Hard water that tests between 11-22Dgh (200-400ppm)

Soft water is best for discs, neons, cardinals etc.
Hard water is best for Rift Lake Cichlids, goldfish,
and brackish water fish

Either of the two "medium" categories are good for the
about all other tropical fish.

As the fish live in the tank, organic waste products are
built up as part of the nitrogen cycle (ammonia-nitrite-
nitrate) and the compounds break apart to form organic
acids. These acids cause the waters' pH to drop and
tend to become more acidic. (below 7.0, down into the
6s) The carbonate ion will buffer that change (neutralize
the acids) and help maintain a more steady pH.

Generally speaking, a GH or KH reading between 3 and 6
is ideal. Nearly all of our fish are "farm grown" and
can live quite comfortably within the "medium" range of
GH&KH. Some, such as the Discus, and rifts prefer the
extremes.

Most of us are specific when we address the hardness of
water and state either GH or KH when writing.
With a reading of 2 that would be good for any of the
teras, discus and many other fish. It would not be
ideal for swordtails, mollies, guppies etc.

To raise the GH you can add crushed coral, crushed dolomite,
or crushed oyster shells to the substrate and over time
it will increase the GH. However weekly water changes
will be necessary to "dilute" the hardness over time. Or,
you can put some of the above into the toe of a panty hose,
tie it off, and put it in the output of your filter so the
water flows through it on the way back to the tank. Then
you can test regularly, and remove it or replace it as the
GH varies.
To raise the KH (only) you can add regular old UNSCENTED
baking soda to the water, a teaspoon at a time, wait 24
hours for it to mix, and test and add more if necessary.

Hope this helps...

Frank


Last edited by FRANK at 27-Jan-2005 09:58

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Gee,

Since the lfs did not mention which hardness needs to be "hardened", I will assume that it is the KH or carbonate hardness. The caution that I think the lfs is giving to you is that a low KH, say under 3 degrees of German Hardness, makes your aquarium susceptible to a pH crash or a rapid drop in pH. Crashes can kill, injure or stress you fish.

As Frank mentioned, baking sada will raise your KH. Your target shoukld be above 3.

__________
"To steal ideas from one person is plagiarism; to steal from many is research."
researched from Steven Wright

Thankyou for your replies :-)

My LFS told me to harden KH, and sold me some sort of liquid product that could be used to modify it over several days.

What I was worried about was what kind of hardness people mean when they talk about different species... So, as an example, when you say 'soft' water is good for Cardinals, do you mean soft by KH or GH standards?

The hardness level on the Cardinal Tetra profile says 5 --&gt; 12 dH, but is that likely to be KH or GH? &lt;confused&gt;

If you have to raise your carbonate hardness (kh) what they sold you is likely baking soda in a liquid form, the same type you may have in your kitchen right now.

Ajusting ph with products like ph up or ph down (as sold here in the states not sure their availiblility overseas) will often cause nothing but trouble since they dont work long term and will just cause stress from the PH swings.

Does the product your LFS sold you have a list of ingredients?

Since it's to be used over a period of days that's a good thing slow ajustments are the best when it comes to fish.

^_^
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Hi,

The product in question is dissolved CacO3, so not exactly bicarb... It says its designed to make changes of 20 mg/L / ppm per day.. As I understand it, this means changes of 1 --&gt; 1.1 dKH.

I have used pH adjusters in the past, but as you say, they aren't all that great. :-(

Something I've noticed - although I've been using this stuff precisely as directed, my pH is *soaring* - it's gone around 0.8 units in two days :-( Is this normal when using a KH increasing product?

Hi,
I guess I sortof hinted in my previous post...
When we talk about say, tetras, needing "soft water"
we are all speaking of the General Hardness (GH).
The while claiming the same last names, are separate.
One measures the amount of Ca and Mg ions, and the other
the amount of carbonate, and bicarbonate ions.

You can adjust one, the KH without affecting the other
by the use of regular unscented baking soda. If what
you add affects the GH then it will affect the pH of the
water, generally increasing it as it becomes harder.

Water that is above a pH of neutral (7.0) is considered
to be Alkaline and has a hardness that ranges from the
medium hard to hard (at pH 8.0).

Since you want to increase only the KH, simply go to the
grocery store and buy some Arm &amp; Hammer, unscented,
baking soda, and use it. It will be far less expensive
than what the LFS is selling, and not affect the other
values of the water. Do note, however, if you add the
baking soda, it will buffer the acid value of the water
and the pH will slightly change, generally upward.

Generally speaking, you would want to aim at about a
KH of three.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Now I'm totally confused :-P

When I spoke to the staff at my LFS, I got told that GH was unimportant compared to KH, which needed to be high to buffer pH changes.

In terms of alkaline water being hard - my tap water reads KH 1 --&gt; 2, and pH 7.3 - what does this mean? :-P

NZ tap water is held to the highest standards for human consumption, but something tells me it may not be so good for the fish :-P

Hi,
There are any number of things that affect the pH of the
water. You have dozens of members from NZ here on the site
and most are very knowledgeble. Whetu for instance.

Your water is fine as it is with the values it you have
given. Most would prefer a KH of 3, but at 2.anything,
you would be "shaving hairs" if you set your sights on
3 and work hard to reach it and keep it there.

Three is a kind of "mythical figure" because below that
with lots of plants, and especially with CO2 being
injected, or with an over stocked tank, the pH can swing
even more than 1 point between lights on and lights off.

During the day the process is for plants,active fish,
and light, to interact. The plants soak up the CO2
and provide O2. The pH will swing in a higher direction.
At night the plants switch to using O2 and of course the
fish are using O2, and the pH will drop.

These daily (24 hour) swings in pH can be taxing to the
fish sometimes stressing them into illness or death.
Most fish will adapt to live at nearly any sensible pH
as long as it is stable.

Stability is the key.

With a KH of 3, the recommended minimimum, especially for
those with CO2 injection, the swings are buffered by the
carbonate ions. This means that the normal pH swings
between night and day, are minimized and all is well
within the tank.

Generally speaking, your readings mean that you should be
able to keep most tropical fish and live plants that are
available on the market. And practically speaking, you
could keep everything save Discus or African Rifts.
Since very nearly every fish in our tanks has been farm
raised, they are acclimated to the 7.1,2,3 pH water already.

Frank


Last edited by FRANK at 28-Jan-2005 10:24

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Again, thankyou very much for your reply.

So (just to summarise) - this product I have purchased is raising KH as well as GH, which is forcing the pH upwards... What I really need to do is raise just the KH by one or two dKH from tap water to stabilise it?

Sorry for asking the same question ten times over - I have some background in Biology, but I'm afraid inorganic chemistry has never been my strong suit :-P