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Old 8th January 2008, 02:31 PM   #14 (permalink)
Natureboy
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Default Re: New 100 Watt Lamps - Meter at 18. Is this normal?

Quote:
Originally Posted by solarmeter® View Post
What "percent UVB" are the lamps supposed to be?

The higher the percent B the lower a 5.0 meter will read for a given wattage lamp. It is not uncommon for some base bed high-B 100W's to read only 16-18 new. Old-era lamps sacrifice UVA (which is mostly what the 5.0 meter reads) to get more UVB (which is what the 6.0 meter reads).

Bottom line is your new lamps would be "hotter" on a 7.0 MED/hr meter and a 6.0 UVB meter for reddening rays... but not much better than the old ones for UVA tanning rays. Above 20 on a 5.0 would be more typical.

New-era lamps peaking at 365nm UVA read quite a bit higher on the 5.0, somewhat lower on a 6.0 UVB, and usually about the same as old-era on a 7.0 MED/hr meter.
This is exactly right. My Sundash base beds I went from a 5% UVB lamp that metered 35 new to a 6.5% lamps that metered 25 new on a 5.0.
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