🚀 go-pugleaf

In article <1992Nov21.164728.16086@vax5.cit.cornell.edu> mdkj@vax5.cit.cornell.edu writes:
>I have been keeping plants in my two tanks for quite a while, and although they
>grow well, they tend to stay smaller than what they were when I originally
>bought them.  As an example, I bought a giant amazon (A. bleheri) 6 months ago
>with leaves (plus stems) that reached about 15 in.  Now, all new leaves are
>only half that size (most of the difference is in the stem).  The same happens
>with my cryptos and hygrophilas.  

The difference in stalk length of the sword plant could be because the
plant you bought had been grown in crowded conditions, forcing the
leaves to grow longer to reach the light.  Still, 8" is rather small
for an E. bleheri leaf.  I have noticed that some species of crypts
(C. nevilii for one) tends to have smaller leaves in my tank.  I think
this was probably because the plants I bought had been grown emersed.
However, Hygro species usually have larger (and sometimes dramatically
different) leaves under water than above, so you should not be seeing
a reduction in their leaf size.  What species of Hygrophila do you have?
 
>I add weekly iron and trace elements, and have laterite in the bottom gravel. 
>I use 3 40W Triton bulbs on the 70G tank and a reverse-flow Eheim undergravel
>filter.  I have a relatively small amount of
>hair algae among my floating plants.
>My question is: could this lack of "big" growth be the result of CO2
>deficiency? 

You could try adding a couple of 40W lights.  But if you are asking
whether your plants will grow bigger with CO2 than without, my experience
says yes.  I am sure most people who use CO2 injection will agree that
it is the most important aid to keeping lots of large, healthy, fast 
growing plants.

>If so, what would be an acceptable level and how is it reachable
>(preferably without having to buy a $$$ diffuser...)?

About 10-20 ppm of CO2 is good.  I don't know of any cheap (less than
$100) way.  The FAQ on plants has information on CO2 injection.

-Shaji.



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Shaji Bhaskar     BNR, Research Triangle Park, NC 27709     (bhaskar@bnr.ca)