re:Plants in A Discus Tank

>From: Ron Rodriguez <rrdgez at houwork_com>
>Date: Tue, 5 Dec 1995 18:55:16 -0500
>Subject: Plants in A Discus Tank
>I'm 6 weeks into my new tank set-up (180 gal,2-2217 Eheims,15watt UV).  Water 
>is setting up rather nicely.  I'd like to keep my water temperature high at 86 
>degrees for the discus. What kind of plants would you recommend?  I'm 
>utilizing 6 Coralife 50/50 30-watt bulbs with external reflectors.  How long 
>should I keep them on?  I've also heard you can minimize algae growth by 
>utilizing a timer and turning the lights on/off over an extended period of 
>time and still getting the 10-12 hours most people recommend 
>(Ex.6:30am-8:00am;10am-noon;3pm-5:30pm;7pm-11pm for a total of 10 hrs).  Is 
>this true?

Your UV sterilizer may oxidize trace nutrients that your plants need.  I 
haven't used one, but I think some others on this list may have done some tests 
with them.

If I read your message correctly, you have 1 watt/gallon in your tank.  I'm of 
the opinion that really big tanks don't require the 3-4 watts/gallon ratio that 
medium-sized tanks seem to do best with, but 1 watt/gallon is pretty sparse.  
With this in mind, you might go ahead and shoot for 12 hours of lighting per 
day instead of just 10.  You'll probably need to experiment for a while to 
figure out what works best for your setup.

Stem plants:  H. polysperma, H. difformis,  These may not grow very fast in 
your low lighting situation, but if given proper nutrients, they should at 
least grow some.  Maybe some rotala indica, but only if you don't break your 
lighting into short periods.

Rosette plants: C. wendtii is the only one I have experience with that I think 
will do well in this little light.

Rhizome plants: Anubias sp, Java fern, Java moss

Floating plants:  Duckweed, Hornwort

Bulb plants: A. crispus (Maybe)

Other plants that I don't have experience with will probably work too.

My opinion on breaking your lighting up into several periods (after trying it 
for several months) is that it gives your algae an advantage over the plants.  
Plants seem to photosynthesize very slowly when the lights first come on, 
building to a point in the afternoon when photosynthesis is highest, and then 
dropping off quickly when the plant completes its photosynthetic cycle for the 
day.  Plants also seem to do most of their growing while the lights are off.  
If you break the lighting period up, your plants don't seem to have enough time 
to "get into" either the photosynthesis or growth portions of the cycle.  Algae,
 on the other hand, seems to be able to photosynthesize any time the lights are 
on.  It also seems to grow pretty much only when the lights are on.  
My opinion on "thunderstorm" periods is to leave them out altogether.  Instead, 
I use "hurricane" days about once every 2-3 weeks.  A "hurricane" day or days 
is when I turn off my timers for up to three days.  I sometimes also cover my 
tank to completely black it out.  When I do this, my plants (and fish) go on 
their energy reserves.  The plants will often grow quite a bit during this 
time.  Algae quickly runs out of reserve energy and does not replicate much at 
all during this time.  The result is:  When the lights come back on, my plants 
have grown quite a bit, and the algae has actually died back some.  I've found 
this method to be especially effective against red algae, and somewhat less 
effective against blue algae.  I understand that it will also eliminate green 

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc. Dallas, TX USA
(214) 575-3443 (voice)  MSGID:       DAWB
(214) 575-4853 (fax)    Internet:    dwebb at ti_com
(214) 581-2380 (pager)  Text Pager:  pgr at ti_com Subj:PAGE:David Webb