Ccapt I guess my ? is how good are them $25 ballast?
Good enough that I have the same 1, and it's still working perfectly, that I started with 20 years ago. I bought the 2nd when I upgraded from a 3' 50g breeder to a 75, then I bought a 3rd when I upgraded to my current 125.
As far as color differenct between different ballasts, look at this
chart. It compares the performance of the same bulb using 4 different ballasts. CCT is Correlated Color Temperature, which is the actual Kelvin temp of the bulb as tested. The magnetic ballast will make the bulb look slightly more blue compared to the electronic while the electronics give a little better PPFD.
The bulbs for MH are 2 to 3 times as expensive as T5 bulbs, and need to be changed twice as often. I spend $300 every 6 months in replacement bulbs.
That is highly debatable. Typically, a 48" 54w T5 bulb runs about $20. 3x54=162w @ $60. 1 175w MH runs about $60. Basically the same price.
From the article
Metal Halide Lamps - Aging Over Time by Sanjay Joshi
"The lamps were operated by standard magnetic (ANSI M59) ballasts, and lit for 12 hours/day. Before using the lamps, the spectral output was measured, and the data collected is shown in table 2, and the spectral distribution is shown in figure 1."
and...
"The initial plan for these lamps, was to measure the output when they were put into use and then measure the final output when the lamps were replaced. Based on my past experiences with metal halide lamps, the plan was to replace these at 15 months of use."
and...
"The data showed some surprising information. The output PPFD of the lamps showed a slight increase in one of the lamps, while the other stayed almost the same. If one were to use a quantum meter to measure the output to determine if the lamp should be changed, it would show little change in output even after 17 months of use. The spectral plot shows where the changes occurred over time, and as expected there is a drop in the blue spectral region, but there was an increase in the spectral range from green to the reds, which made up for the lost output in the blue region. This also clearly shows in the drop in color temperature from the 10000-11000K range when new to 6000-7000K range after 17 months of use."
MH use soooo much more power than T5s, it's ridiculous. I run my MH for only 8 hours a day, and it has added an extra $200 a month to my electric bill.
I don't claim to be an electric expert by any means, but doesn't 200w cost the same to run wether it's a 200w light bulb, 200w microwave or 200w heater? A MH ballast may pull more power to fire the bulbs, but once they are lit, how does a watt of light from that cost more than a watt of anything else?
