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Old 20-04-2003, 06:21 AM
Lee Clemmer
 
Posts: n/a
Default Elodea suddenly "rots"--why?

Hello all,

I'm having a problem in my 29 gal. tank.

The elodea, which normally grows very fast, between 1/4" and 3/4" per day,
suddenly begins to disintegrate partway up the stalks.
Symptoms are a lack of chlorophyll, the stem and leaves become translucent
and all green goes away over the course of a few days. The growing tips of
the plants remain green but with reduced growth, a very short inter-nodal
length and the new leaves are "clamped" against the stalk.
After a few days the stem comletely dies in the area where the problem
began. Next the death spreads down the stalk toward the roots or base. Until
this point the lower portions of the plant usually remain green and appear
healthy.

I can't seem to match these symptoms with an obvious deficiency, maybe I'm
reading too much into the deficiency descriptions and it's something
blindingly obvious?

What adds to my confusion is that the other plants are doing VERY well.
Several sword types have excellent color and are putting out new growth. The
bronze crypts are growing well & spreading. The Hygrophila polysperma is
doing better than it was recently, with better leaf size and growth rate.
The corkscrew val. is still spreading via runners. The val. however is
showing some yellowing on older leaves but they might just be old--I'm not
sure if this is related or not. Java moss is "reclaming" sections of the
tank at a decent rate.

Any thoughts? Why is this one plant species rotting away?

Tank parameters:

Temp 74 deg. F
Flourite substrate with minor amount of gravel & clay present lots of mulm
in substrate.
pH 7.0
KH = 2 deg. (this is adjusted with baking soda during water changes, tap
water tests between 0 and 1 deg)
GH = 4 deg.
Ammonia = 0
NO2 = 0
NO3 = ? somewhere between 2.5 and 10 ppm depending on the test used.
This value is problematic because the two tests (liquid only reagents
vs. powder reagent) both seem to indicate a clear value. Perhaps I should
take the "middle" value on the chart and say it's 5 ppm? I know this value
is important but the tests are frustrating. Water out of the tap shows 0 for
both tests.
Nitrate is added via KNO3 in homemade PMDD.
Phosphates = ~.25 ppm.
Iron = .1 ppm. Iron is added via trace element mix. (Flourish trace)

Light is a whopping 3.7 watts/gal via a dual compact flourescent fixture.

CO2 has only been running on the tank for 2 days via DIY method. The problem
described with the elodea began before the CO2 was added. I'm not sure how
much exactly is there. The "chart" or calculator suggests 6 ppm. (bubble
rate is currently 1 bubble about every 4-6 seconds) Bubbles get injected
into the input of a powerhead and come out in a cloud of tiny bubbles. Some
of the gas never dissolves as the bubbles float to the surface.

Any general observations would be very much appreciated and any insight into
the main question:

Why the heck is my elodea disintegrating?

Thanks,

Lee




  #2   Report Post  
Old 20-04-2003, 06:21 AM
Bugbear
 
Posts: n/a
Default Elodea suddenly "rots"--why?

I would have to say that the water temp is to warm for elodea. It is
a plant that does best in colder water, around the mid 60s. Even
though it is widely sold by many LFS, it naturally grows in slow
moving water that is cool. Someone else may have more insight on the
problem. The above is from my observations.

Good luck.



"Lee Clemmer" wrote in message ...
Hello all,

I'm having a problem in my 29 gal. tank.

The elodea, which normally grows very fast, between 1/4" and 3/4" per day,
suddenly begins to disintegrate partway up the stalks.
Symptoms are a lack of chlorophyll, the stem and leaves become translucent
and all green goes away over the course of a few days. The growing tips of
the plants remain green but with reduced growth, a very short inter-nodal
length and the new leaves are "clamped" against the stalk.
After a few days the stem comletely dies in the area where the problem
began. Next the death spreads down the stalk toward the roots or base. Until
this point the lower portions of the plant usually remain green and appear
healthy.

I can't seem to match these symptoms with an obvious deficiency, maybe I'm
reading too much into the deficiency descriptions and it's something
blindingly obvious?

What adds to my confusion is that the other plants are doing VERY well.
Several sword types have excellent color and are putting out new growth. The
bronze crypts are growing well & spreading. The Hygrophila polysperma is
doing better than it was recently, with better leaf size and growth rate.
The corkscrew val. is still spreading via runners. The val. however is
showing some yellowing on older leaves but they might just be old--I'm not
sure if this is related or not. Java moss is "reclaming" sections of the
tank at a decent rate.

Any thoughts? Why is this one plant species rotting away?

Tank parameters:

Temp 74 deg. F
Flourite substrate with minor amount of gravel & clay present lots of mulm
in substrate.
pH 7.0
KH = 2 deg. (this is adjusted with baking soda during water changes, tap
water tests between 0 and 1 deg)
GH = 4 deg.
Ammonia = 0
NO2 = 0
NO3 = ? somewhere between 2.5 and 10 ppm depending on the test used.
This value is problematic because the two tests (liquid only reagents
vs. powder reagent) both seem to indicate a clear value. Perhaps I should
take the "middle" value on the chart and say it's 5 ppm? I know this value
is important but the tests are frustrating. Water out of the tap shows 0 for
both tests.
Nitrate is added via KNO3 in homemade PMDD.
Phosphates = ~.25 ppm.
Iron = .1 ppm. Iron is added via trace element mix. (Flourish trace)

Light is a whopping 3.7 watts/gal via a dual compact flourescent fixture.

CO2 has only been running on the tank for 2 days via DIY method. The problem
described with the elodea began before the CO2 was added. I'm not sure how
much exactly is there. The "chart" or calculator suggests 6 ppm. (bubble
rate is currently 1 bubble about every 4-6 seconds) Bubbles get injected
into the input of a powerhead and come out in a cloud of tiny bubbles. Some
of the gas never dissolves as the bubbles float to the surface.

Any general observations would be very much appreciated and any insight into
the main question:

Why the heck is my elodea disintegrating?

Thanks,

Lee

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Old 20-04-2003, 06:21 AM
Lee Clemmer
 
Posts: n/a
Default Elodea suddenly "rots"--why?

Leigh,

Thanks for your reply.

Yikes! That's too way too much light to have on a tank without CO2

injection.
You need to get your CO2 levels up.


That's what we're working on now with the DIY setup.

Relevant points. Yes it's a lot of light
I guess my casual response is that TMTOWTDI! When I had lower wattage
fixtures everyone here insisted that I needed MORE light! I certainly know
that you can have too much of a good thing, and that this light level is
rather high. I have/had been using Flourish Excel as a supplemental source
of carbon. I never took the time to set up the CO2 system although it was
rather easy to do. The tank did well with a different group of plants with
low light and no CO2--no surprise there.

The plants were growing well, as was the Egeria, without any CO2 addition
and with minimal additions of Excel. They grow/grew well for months. Algae
problems that were easily remedied came and went depending on changes in
fertilization. There's probably more algae there than you or some of the
crew would accept, but it's not much. Recently the algae problem was "fuzz"
that covered some leaves, a bit like razor stubble a few days old. This is
going away with the addition of more NO3. The snails are cleaning up as
well.

Almost all the plants were PEARLING without the addition of CO2. The high
light conditions no doubt had the plants sucking as much CO2 out of the
water as possible, possibly leaving very little.
Some of the plants might have the ability to use carbon from carbonate, as
some algae can. Tom or George mentioned this recently in another thread. I
can't speak to this issue in detail but the tank constantly needs the
addition of bicarbonate to maintain any measurable KH.

How long has this tank been set up with that lighting? And how do you

keep the
temperature at 74 degrees with that much light over the tank?


It's been at least 6 months. The room temp is 70 degrees F. The light is
separated from the tank by a 3/8" piece of glass, and the front and back of
the top of the tank are open along the length of the tank; 3/4" slits all
the way across, allowing heat to escape. It's not a closed hood. I just
checked the temp again and 4" deep into the tank it's showing 73 deg. I
guess there's just not that much of a heating effect with this setup.

The temp hasn't changed since that plant was introduced, so the original
question remains, why is the stuff rotting now?

Thanks again,

Lee


  #4   Report Post  
Old 20-04-2003, 06:21 AM
Lee Clemmer
 
Posts: n/a
Default Elodea suddenly "rots"--why?

I would have to say that the water temp is to warm for elodea. It is
a plant that does best in colder water, around the mid 60s. Even
though it is widely sold by many LFS, it naturally grows in slow
moving water that is cool. Someone else may have more insight on the
problem. The above is from my observations.


Thanks,

Now that's an interesting thought, Leigh mentioned it as well.
One variable here that has changed is the *location* of the heater in the
tank. I moved it over to the Egeria's side of the tank a while ago. It only
comes on at night, but perhaps the *local* temerature in the tank near the
plants in question gets too hot. The heater may have been creating a hot
spot in that area of the tank, as circulation was not great. The powerhead
injecting the CO2 has added a lot more circulation but it may be too late to
save this group of plants.

Lee


  #5   Report Post  
Old 20-04-2003, 06:21 AM
Lee Clemmer
 
Posts: n/a
Default Elodea suddenly "rots"--why?

David Whittaker on the APD suggests that this is due to a critical shortage
of calcium and that the plant does not like the level of sodium vs. calcium.
This sounds reasonable since I have adjusted carbonate hardness with sodium
bicarbonate rather than calcium carbonate.

A good source of calcium carbonate that is inexpensive should be easy to
find.

Lee




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Old 30-07-2011, 12:10 PM
Registered User
 
First recorded activity by GardenBanter: Jul 2011
Posts: 1
Default

Quote:
Originally Posted by Lee Clemmer View Post
Hello all,

I'm having a problem in my 29 gal. tank.

The elodea, which normally grows very fast, between 1/4" and 3/4" per day,
suddenly begins to disintegrate partway up the stalks.
I'm having the same exact problem. It is almost as if something in the water is dissolving the elodea. I just found out that my pH decreaser is phosphate based. So I have been pumping phosphates in my tank. I have since stopped. I will let you know if this solves the problem.

I'm keeping a photo-log:

Daphnia vs. Green Water


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