Re:Calcium deficiency problem?

[krombhol at teclink_net (Paul Krombholz)]

>From: "pieter cool" <pieter.cool at esat_kuleuven.ac.be>

>My swordplant's new leaves are almost white. The new leaves are also a
>little curled.
>I think it is a Ca problem.
>What I don't understand is that my Kh and Gh are about 10 dH.
>When I do waterchange I do it with water that has a Kh and Gh of almost 0
>dH.
>My tapwater has a Gh of 27dH and also a very high Kh. To lower these
>values I use an ion-exchangers.
>I think that there's an exchange , the Ca and Mg to Na.
>The strange thing is that the water in the tank stays at 10 Gh and Kh.
>Perhaps it is the substrate  I use in the tank. Perhaps it releases
>chemicals other than Ca in the water that
>higher the Kh and Gh .
>Or there might be shells in the substrate that release Ca in the water.
>When this is the case , I don't understand the problem of my swordplant.
>An other thing I've noticed is the shell of the snails. I can almost look
>through it.
>This also looks like a Ca deficiency to me.
>
>If someone could help me with this , I would be very gratefull.
>Excuse me for my bad English but I'm from Belgium.
>

It doesn't entirely sound like a calcium deficiency problem.  With calcium
deficiency, the new leaves become badly distorted and shrunken before there
is very much white in them.  The white tends to come in streaks  and
patches.  When calcium deficiency is so bad that the new growth is entirely
white, there is almost no new growth, and the meristematic region dies.  I
think that iron deficiency might be likely here.  There may be calcium
deficiency, too.

When you use ion exchangers on hard water you usually get sodium released
as calcium and magnesium are taken up.  You may have a lot of sodium
bicarbonate in your water.  This would contribute to KH (alkalinity), but
not GH (measure of amount of Ca and Mg).  Remember that both magnesium and
calcium contribute to GH.  A GH reading does not automically mean that you
have calcium.  Magnesium could be the only contributor.

So you may be low in calcium, but from the symptoms you describe, you
should also consider iron deficiency.  To add calcium rapidly, use ordaniry
lime,  or ground limestone, about one or two cubic centimeters per 50
liters.  Add CO2 to get it dissolved even  more rapidly. As far as iron, I
have always found that swordplants grow well in a mixture of soil and peat.
They also respond to additons of chelated iron to the water.  Iron EDTA
works, but iron DPTA works a lot better because it stays in the water a lot
longer.

There is no need to apologize for your English.  You write and spell a lot
better than millions of Americans.

Paul Krombholz in dry central Mississippi.