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Re: Ca Deficiency

On Tue, 8 Jun 1999, Elliot Williams wrote:

[snip tidbits]

> Now (at long last) my question:  I have what appears to be Calcium
> deficiency in the swords.  Brown streaks on diagonal veins, raised/thick
> center vein, thinner leaves, sometimes slightly gnarled/cupped.

When did the symptoms appear?  E. bleheri and other swords are
commerically grown emersed.  When we put them under water in our tanks
their new leaves are different from the emersed-grown leaves.  E. bleheri
and other similar swords grow narrower leaves, usually on shorter
petioles, and young leaves especially have brown diagonal veins.  Those
probably disappear as the leaf ages.  The leaves are often slightly
spiraled and the leaves may be slightly bent into a scimitar-like shape.
That is all pretty normal.

> H.
> Difformis has been growing bent and horizontally about 1in above
> ground--looks like weak stems?

I don't grow H. difformis, but from what I've heard this is probably
normal as well.

> The trick is that I should have plenty of
> calcium.  I have added at least 3 tsp of Oyster Shell lime (CaCO3) and 10
> mg of CaCl2 over the past month.  Plus 75 ppm Ca in the water, weekly 1/5
> changes.

You probably shouldn't be adding calcium.  With 75 ppm in your tap water
you already have more than your plants should need.  I have less than a
tenth of that in my water.

> Don't (yet) have Ca test; wouldn't think I needed one with the
> hard water. Perhaps a clue, as suggested elsewhere by Roger Miller, is
> sodium.  We have (per water co.) 100 ppm here.

In order for sodium to cause problems the sodium concentration needs to be
*much* greater than the concentration of calcium, magnesium and potassium.
In my tap water for instance, the sodium concentration is more than 15
times the calcium concentration and 100 times the concentration of
magnesium and potassium. Concentrations of calcium, magnesium and
potassium are all low.  Despite the low concentrations of calcium and the
relatively high concentration of sodium, I only see calcium deficiency in
plants grown under bright light with added CO2.  I can avoid the problem
just by reducing the light or letting other plants spread out on the
surface above the sword plants.  That lets the sword plants grow a little
more slowly.

Most of us (Cheryl Hofmann being an exception) will have water with
extreme sodium:calcium ratios only if they use an ion exchange water
softener (Culligan, for instance).  Ion exchange water softeners pull most
of the calcium and magnesium out of the water and replace them with
sodium.  That's great for lathering soap, but not so great for plants.

Roger Miller