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A follow-up on earlier questions (pretty long)
Back in November and again in December I posted questions about problems
with Echinodorus parviflorus(?) and Cryptocoryn crispatula var. balansae
in one of my tanks. I'm posting this to follow up on developments since.
On Nov. 22 I asked about folded, rigid leaves on a small and slow-growing
sword plant in a soft water tank with an aged gravel substrate. I
received replies both on and off list. My thanks to all who replied. The
prevalent idea was that the symptoms were caused by a calcium shortage,
and the advice was to add calcium.
I'm not real keen on chemical dosing and tend to look for other solutions,
so I held off a bit and looked for other ways to solve the problem.
I wanted to move the plant over a bit for purely aesthetic reasons and
that gave me a chance to check the plant in more detail. When I uprooted
it I found very little "mulm" in the substrate around the plant. Also, I
noticed that it had a 1-inch rhizome and that most of the roots on the
older part of the rhizome were dead or dying. I cut off most of the
rhizome. The newer roots were about 18 inches long (on a plant with
4-inch leaves!), coarse and almost entirely unbranched. I trimmed the
roots down to about 10 inches, and replanted. On the same day I checked
out the tubing I use to circulate water in the substrate and found that
the venturi that drives the circulation was plugged. I don't know how
long it was plugged, but I cleared it.
After all that I waited a few weeks to allow the plant to reestablish.
New leaves developed in that time were still folded and rigid. I then
tried a kitty litter amendment - the idea being to provide the roots with
fine grained material to promote root hair development and some CEC to get
cations like calcium retained near the plant roots.
I cut the end off a large syringe (supplied with a Tetra Laborette) so it
could be used as an open-ended plunger. I mixed aquarium gravel with a
small amount of kitty litter and put "slugs" of the mixture into the
plunger. Then I submerged it with my finger partially covering the open
end of the plunger, held it so that air could escape and the mixture would
get wetted, and plunged the mixture into the lower part of the substrate
at intervals around the plant. I concentrated it mostly in areas where
I positioned the plant roots. I placed 8 slugs, each about 10 cc.
The first leaf that developed after this treatment was still folded. The
second leaf was not folded. Since that time the new leaves have nearly
doubled in size (each is more robust than the last) and none are folded or
The plant is about to outgrow its niche in the tank and so pretty soon
I'll be uprooting it once more to move it to a more appropriate location.
Then I'll know whether any of the manipulations had the physiological
effect I wanted, or whether the change was caused by something else.
More recently on Dec. 27th I asked if there was some way to get my C.
crispatula v. balansae to retain more fully developed leaves. The plants
typically supported only two fully developed leaves at one time, and
dropped one leaf when a new leaf developed.
The advice on and off list was to fertilize the substrate, but different
people gave different reasons for doing so - some said to add P some to
add N. Thanks to those who responded, but again I didn't want to add more
fertilizer, so I waited while I looked for a different solution.
Well, with no obvious action on my part the plants started retaining
leaves. They now have from 4 to 6 fully developed leaves all slightly
longer than they were before. They're adding new leaves as they did
before, but they aren't dropping old ones.
The plants are nearly 3 feet away from the area where I amended the
substrate and the change occured more than a month after I unplugged the
substrate circulation, so I doubt either of those changes had a direct
effect on the balansae.
At the same time the plants started retaining leaves and for unrelated
reasons I put an outlet manifold on the powerhead. The powerhead was used
to circulate water, disperse CO2 and (with its venturi) drive the
substrate circulation. Previously, the powerhead discharged directly over
the balansae. This was not a detail I described in my original question.
The high-velocity discharge kept the leaves bent over but didn't cause
damage that I ever saw. The manifold produced lower discharge
velocities, distributed over a larger area. It still discharges partly
across the balansae planting but it doesn't push the leaves down as hard,
or move them around as much.
The change in the discharge is the only thing I can think of that directly
effected the balansae. I find it hard to believe that it would have that
much effect, especially since Rataj and Horeman describe C. balansae
growing naturally in fast-moving streams. Has anyone observed a tendency
for balansae to be damaged by water movement?