Re: [APD] lighting on the cheap

["S. Hieber" <shieber at yahoo_com>]

I just had my six shots of espresso so I guess I'll step in here and comment on the statement that T5HighOoutputs last longer than compact fluorescents.
 
I hear this now and then, so I know it gets stated and restated and quoted and passed around but, imo, it belongs on the list of myths in the aquatic hobbies; along with air bubblers are always good; charcoal is always your friend; charcoal is always wrong for a planted tank; there's one best way to add CO2 to a planted tank; UV lamps will keep your plants from getting iron; sumps don't effect CO2 loss, and CO2 should be shut off at night because God and Nature want it that way.
 
Production lines are newer and prices are higher for T5HOs so maybe that's why the prices tend to be higher, but power compacts do not need replacement any more or less often than T5HOS. A 55w PC  (PL-L) is virtually the same thing as a 54w T5HO, except folded into a U-shape -- it's a 4-foot, 54w HO, 5/8s diameter tube with essentiallythe same operating parameters as the straight tube T5HO. There's no special unique technology in a T5HO that's not in 55w PC -- the shape is the only "new" thing about the T5HOs and then only for those 3 feet or longer.
 
Part of the myth about PCs needing to be replaced every year or every 18 months comes from the VHO bulbs that were basically ruggedized NormalOutput bulbs intended to be severely overdriven -- (IceCaps underdrive them at about normal output so that they have output and longevitiy like a NO ;-) )  All incandescent and arc lighting devices (fluorescents, MHs, sodiums, etc) and non-arc fluorescent lighting devices (superbright LEDs) yield less ourput the longer they are used but the rate of decrease slows with use. For PCs (or T5HOs), the diff in output during the first couple of months is marked but between 12 months and 18 is negligible. Even newer MHs can maintain their spectrum and output longer than they used to. Put a bunch of comparable quality T5HO and 55w PC on identical ballasts and they will perform comparably, last comparably, die comparably (well, once yuo average over the diffs between individual bulbs in each group since their can be outliers in any group ;-)  
 ).
 
T5s are an excellent choice for lighting a planted aquarium but their only virtue over u-tube (PL-L) compacts is that with certain reflector arrangments you can avoid more of the restrike -- i.e., you can keep the tubes farther apart and less light hits the tubes, but the diff is relatively small, not nearly so much as the diff between u-tube compacts and coiled tube compacts. OTOH, T5HOs do tend to cost more than compacts (although the prices eventually should drop dramatically once they come into wide use in office bldg.s). So, I agree one should consider them but, imo, one shouldn't pay much more for them.
 
sh
 

----- Original Message ----

 
I'll make the pitch for T5HO ... it's not cheap, but neither are any
of these other solutions, they just have a lower up-front cost, but
higher operating costs as well as more frequent bulb replacements. . . 
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