1¾a starter tank I spent several weeks reading and prowling shops to gain as 
much insight as possible.
One of the major problems and expense I've encountered is the same as years 
gone by, lighting.  To successfully maintain a reef tank, the hobbyist is 
faced with a $600 bill for lighting.
Being frugal in nature and more than accomplished at building things, I have 
naturally sought an economical alternative to the equipment offered by the 
aquarium trade in shops and mail order.
An electronic ballast will run about $170 for one capable of powering four 4' 
long 110w bulbs.  Magnetic ballasts are about $70 capable of two similar 
bulbs.
Home Depot offers a ballast for $35 capable of powering two 4' 110w bulbs.  
Two ballasts would represent the cost of a single mail order ballast.
Electronic ballasts are reported to reduce flicker due to the 60 cycle and 
are much cooler.  The fix I have for the heat is to mount the ballast 
externally and attach a heat sink which will dissipate heat to room air.  The 
60 cycle flicker has not as yet been proven to be a factor in the successful 
maintenance of a reef tank.  However, there are several ways of mitigating 
the flicker.
First, is to run separate phases and power either two or three ballasts on 
individual phases.  Since homes are wired with three phase 240v anyway, it's 
not much of a problem usually to run two more breakers thru the system and 
provide three phase power to lighting to offset the affects of the flicker.  
Another possibility is to reverse the hot and nuetral supply on the ballast 
thus further reducing the flicker.  The ultimate conclusion to this drill is 
six ballasts powered from three phases with hot and nuetral reversed on three 
of the ballasts.  For my system I'm planning a two phase, two ballast system. 
 Before anyone crys foul at this, keep in mind that the lifetime of a ballast 
is for a major part, determined by the load, more ballasts and smaller load 
results in longer life and lower overall lifetime costs.  Plus, if you are 
operating on a budget, such as I am, setup costs can be kept low with 
expansion being accomplished as funds are available.
Does anyone know if the magnetic ballasts available mail order are in fact 
any different from the ballasts available at half the price from stores such 
as Home Depot?  If so, is there a difference which would affect performance 
such that it would have an affect on a reef aquarium?
Also, I'm vaguely aware of output buffer circuits which can be applied to 
ballasts to reduce flicker as well as reduce load to the lamp but not the 
ballast.  These do somewhat affect light output from the lamp but again, 
powering a lamp at 100w vs 110 would greatly increse the operational lifetime 
of the lamp.  On a four bulb system this would be about a 2% reduction in 
w/gal.  Not significant I think.  Anyway, does anyone have a circuit diagram 
I could get for this buffer?
Last question, what's the story with metal halide?  I know it needs a ballast 
and bulb.  What is the voltage of the output from the ballast?  I can get 
virtually any transformer from Radio Shack and the rest of the components for 
about 1/4 what they're being sold for mail order.  Unfortunately, I have no 
experience with this particular system.
Any insight anyone has would be greatly appreciated.
Thanks in advance.
John 
ForesterÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ
ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ€˙˙%É
--- Blue Wave/DOS v2.20 [NR]
---------------