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Re: T8s for a 55 (was Osram bulbs)

From: Dan Dixon <dandixon at home_com>

>I'd go with four T8 lamps. Try GE SPX 41s or SPX50s, or Philips TL850 or
>TL950s. Mix them if you want, but it's not really necessary.

I have tried these lamps too with good success both individually and mixed.
Of the plants I have tried, the only thing I have never been able to grow is
lillaeopsis but Glossostigma is no problem. So I don't know if the problem
lies with the lamp spectrum or my medium-soft water or my own general
horticultural incompetence.

>No need for two ballasts, just get a four-lamp ballast. I don't think you
>need a ballast factor of 1.0 or greater, either. The Motorola N.O. ballast
>I use has a factor of 0.875. They make H.O. ballasts with factors of 1.25
>or so, but it's overkill IMO. The N.O. ballasts with four 32-watt T8 lamps
>will put out as much as four 40-watt T12s (about 2.9 watts/gal on your

I very agree with Dan except for the bit about the HO ballasts. HO ballasts
require HO lamps. The ballasts that will overdrive NO lamps are usually
referred to as HLO (High Light Output) ballasts. You could use a 1.2 ballast
factor ballast and only 3 lamps and get the same amount of light and better
lamp spacing but I do not think it is worth the trouble unless you have
limited space or intend to build completely from scratch. The four lamp
system is a lot more common and easier to DIY. You have the options of
rewiring a couple of cheap two lamp fixtures with narrow reflectors or you
can buy a 4 lamp fixture and remove it's guts and install it in a homemade
fixture. Option number one is the easier and about the same price as option
number two but number two can fit into a greater number of hoods. Option
number three would be to just to buy two, two lamp fixtures with electronic
ballasts and narrow reflectors. This is the easiest and probably  more money
but no rewiring involved.