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Re: Calcium Additions

On Mon, 31 May 1999, Ken Whelan wrote:
> After some deep thought(and much reading) and some experimentation,   I have
> confirmed that I have(had) a calcium deficiency in my 70 gallon tank.
> Briefly Tank 1 setup.  (The tank with Algae)  This was a brand new tank from
> the store.
> 70 Gallon 48" x 18" x18"
> Substrate: Duplarit G as installed exactly by instructions.
> KH 7 Degrees
> GH 6 Degrees
> CO2 Injection
> Nitrate's running 5-10ppm
> Phosphates running .1 - .2 ppm
> 6ea 48" 40 watt bulbs.   (4 Vita Lite and 2 Chroma 50's)
> Fish:  A Pair of peacock Goby's, mating and soon to be with Fry (I Hope) 3
> SAE's and that is it.

> After adding a teaspoon of Lime within 24 hours my nitrates dropped to 0
> (and I believe became limiting),  my phosphates are at .1.   One week later
> I am seeing good growth in my hygro's and the nitrates are still 0.
> Phosphates are still .1 and I believe I see the algae dying fairly steadily.

*By definition* the first thing that must happen when you increase the
concentration of a limiting nutrient is that there is a burst of growth -
not a sudden decline.  Decreases in other nutrients follow later, after
growth has been elevated for some time.  So calcium was not growth

I see no other reason why you might think calcium is short.  It is usually
the main part of hardness, and your water contains plenty of hardness,
That should mean that you have plenty of calcium.  When plants do suffer a
calcium shortage they show it by producing stunted, gnarled new growth.
Some plants are more sensitive to the absence of calcium then others, so
only one or two plants in a tank are likely to show the early stages of a
calcium shortage.

> Anyway on to my question.     What is the best way to add calcium to my
> water,   Since the 1 teaspoon of lime I added did not change either my KH or
> GH,   How do I know when I am approaching deficiency levels.(other than
> dying plants).

Lime adds calcium, but it also will drive your pH high - so high that it
is used to soften water, because the high pH forces calcium carbonate to

You might be better off using calcium chloride (sold as deicer) and
calcium carbonate (oyster shell).

Roger Miller