Re: [APD] Aquatic-Plants Digest, Vol 26, Issue 23

[Thomas Barr <tcbiii at yahoo_com>]

>Could you please clarify?  Is stable poor nutrients OK for 
>these? 

It can be, depends on lighting, CO2 etc, if the lighting is low,
the substrate deep, decent CO2(or non CO2+ no water changes),
then yes.

>The explosive growth phase for this tank was at
>least two years ago (well, explosive in a relative sense as
it's 
>a low light, no CO2, slow grow tank).  Didn't change the light,
>no new fish,same fish food, etc.  Any idea what might have
>triggered the sudden melt-down?

Yes.

>1. One too many leaves that pushed the demand past some
critical 
>nutrient threshold?

Partly possible.

>2. Change in chlorine level in water supply?

Naw.

>3. Bulb dimness drifted past some critical threshold?

Naw, plants are quite good adapting to light changes that occur
slowly, Crypts more so than most.

>4. Temp change, it was a pretty hot summer and around the time 
> of the melt the temps moderated some?

Definitely can be a cause.

>I've been told they will grow back, and it looks like they are 
>doing so, but wondering if I can do anything to prevent
>melt-downs in the future.
>Regards,
>DJ

Main thing is keep the tanks cool if possible, if the
tanks/plants look peeked, add more food(SeaChem eq also is a
good thing to add every so often.

One thing you did not suggest, the substrate.
After 1-2 years, it needs a decent deep vacuuming/uprooting.

Some organic mulm/matter is good for new tanks....these are very
poor(too poor)in organic matter.

As a tank ages, the accumulation/accretion of mulm builds up to
the pouint where it's no longer good for the substrate and
bacteria and starts to become "sour". Basically too reductive.

Vacuuming it and uprooting will remove the organic
material(carbon)and bring up the redox levels in the substrate.

It's a balance.
As you add more and more reduced carbon to the substrate, the
redox starts to decline, below about 150-200mv is bad.
Plant roots can help increase the redox, but if you remove a
large sword and do too much disturbance to the tank all at once,
this can cause issues also. If the plants stop growing or stunt,
then they will not add as much O2 to their root zone also.

Regards, 
Tom Barr

www.BarrReport.com












		
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