🚀 go-pugleaf

Excellent!

One major mistake was your lumping low & high pressure sodiums (HPS)
together. Low pressure sodium (LPS) is the pure yellow light lamp,
attributes being highest efficiency (& least light pollution in the
sky i believe). Here in the Boston area the LPS lighting is used on
the Mass Pike (Rt. 90?) between Rt. 128 and down town Boston. High
pressure sodium is the very common orange HID lighting seen in parking
lots & roadways etc... HPS lights are slightly less efficient than low
pressure sodium but still is more efficient & cost effective than
metal halide (MH).  I believe the current conventional wisdom is that
HPS is the best overall outdoor lighting solution. Longest bulb life,
cheapest long term cost, good CRI, constant life time light output
etc...  However MH lighting is the best HID choice for applications
that need a high CRI color rendering index such as Ball Parks,
shopping malls etc.... The down side of MH is dramatic drop in output
long before failure, shorter bulb life, & higher overall cost than
sodium.

Also worth mentioning again is the Mercury Vapor. This is the cheepest
up front cost HID lamp. $21 for a 175W @ Home Depot. This lamp has a
low/bad CRI (ugly blue light), low efficiency (1/3 output of HPS), and
sucks as a grow light (some claim it makes a good blue light
supplement). Do not confuse this type of light with a metal halide,
they are not the same.

High Pressure sodium are now considered the #1 best all around hobby
grow light (with metal halide a close second place). In almost all
cases a single 400W HPS will beat the results of a 400W MH. In
addition 2 400W HPS will out perform a combo of 1 400W HPS & MH each.
The High Pressure sodium is available in a color improved version
called Son Agro (Philips?). This version has more blue.

I suggest you pick up a copy of The Growing Edge at one of the
larger magazine racks in your area. This mag. is devoted to indoor
gardening.

Other minor points:
I thought "Daylight" was the first ever fluorescent on the market?
Consider posting to the group alt.hemp