Lighting and Crypt I.D.

Subject: Re: lighting for 8'x2'x2' tank

Steve Pushak wrote:

> You are quite right Alan in asserting that the depth of the tank
> a factor in the intensity of light required. The requirement is 
> on the _volume_ of the tank which determines how much plant mate
> is able to grow in it. Light attenuation is not a factor and vir
> all direct light which enters the top of the water remains in th
> due to internal reflection. The 1/r^2 law does not apply in this
> There was an extensive discussion of this phenomenon a while bac
> APD. To demonstrate that light is trapped internal to the tank, 
> your eyeball right next to the tank glass and look up and try to
> light through the glass. You won't be able to.

While I'm sure that _some_ light is reflected back into the tank, 
there is certainly a fair amount of light loss due to reflection 
off the plants, etc.  It's easy enough to prove this to yourself. 
 Just turn out all the other lights in a room, and try to read a 
book beside the tank... you can.


Subject: ID for Crypt

> I was in the aquarium store and spied a new Crypt specimen that 
> have and I was wondering if anyone can help ID it. The leaf stru
> very typical for Crypt wendtii but the leaf stem is about twice 
> and very white. The roots had a thickened rhizome that was cut t
> the plant. Perhaps this is not a Crypt at all... ??

C. Pontederifolia is very fleshy, and has a rhizome thicker than 
C. wendtii, put each individual plant is still a rosette.  Does 
this match what you're seeing?

Karen Randall
Aquatic Gardeners Assoc.
Boston, MA