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Lighting Fun



Michael D Nielsen wrote:

>I was just reading some of Karen Randall's stuff on Aquarium frontiers and
>ran across a point I would like clarified by anyone who really enjoys
>lighting nitpicking.
>
>Randall states that blue light produces bushy, short plants, something I
>have read many times in the past.  Thinking that I would like my plants to
>have this growth I have an Actinic 03 bulb on one of my tanks.  The plants
>look the same as in other non-actinic tanks.  Randall then states later
>that the actinic bulbs are not really necessary for the planted tanks and
>are more appropiate for the reefers.

Is this the only bulb you have on the tank?  If not, are you sure that the
single actinic bulb produces enough blue light to offset the light from the
other bulbs plus ambient light?  If so, have you seen the spectral curve
for your bulb?  Are you sure that other portions of the spectrum are not
adequately represented?

>This was one reason I included the blue bulb, but also because the blue
>light penetrates water better, thus getting to the substrate more.  Is the
>water penetration really of any importance?  Does anyone know the
>precentages lost in 24" (depth of tank to substrate)?

IMO, not enough that it makes any appreciable difference at aquarium
depths.  OTOH, Amano leans heavily toward green/blue lighting for his
tanks.  To each his/her own.<g>

>One final nitpick that I just want to mention is that Randall states that
>the VHO bulbs need special endcaps, have short lifes and run very hot.
>THis is true of the tar ballasts, but the electronic ballasts do not have
>these problems. 

> I have been using an Icecap 660 for 4 years with normal
>endcaps and bulb temperatures that are similar to the touch between the 4
>foot VHO and 4 foot normal.  Icecap also claims longer bulb life, but how
>can you judge that without accurate light meter equipment.

First of all, I didn't say anything about how hot or cool VHO's run.  I
said that they were similar in efficiency to NO fluorescents, and slightly
less efficient than MH's and energy efficient T-8's.  I have not seen
anything to make me believe this has changed.  

Second, I specifically said that the bulbs should be run on "special
ballasts" (meaning those specifically designed for VHO bulbs) for full
efficiency.  

It was my understanding that VHO's had a different pin arrangement than the
typical bi-pin NO or T-8 lamp.  Is this incorrect?   As far as bulb
degradation is concerned, the reports from other aquarists has been that
these bulbs generally require frequest replacement to avoid greatly
dimished light output.  If Icecap ballasts prevent that problem, that's a
great improvement.


Karen Randall
Aquatic Gardeners Association