I'm not a fan of Zoo-Med anything - 2-5 watts per gallon of water is optimal, the difference between 2-5 would be "Type of lighting system" Metal halide are Hotter - mind you when you add sand and rock your water volume decreases. With reef lighting you get what you pay for - go cheapest and your results will be cheap.
Standard 2 pin flourecent bulbs are pretty much useless when it comes to high band water penetration for corals they just cannot provide the wattage needed. VHO's(very high output flourecents) are down right an electric bill issue and going the way of the dinosaur. T-5 connection type lighting is cheaper, lasts longer, and create sufficent wattage/intesity/water penetration. From there on up ( Power compacts, Metal Halide, LED,T5 HO etc... ) it's pretty much about cost to run, cost to buy, cost to replace, desired look, and also longevity.
Blue (Actinic) Lighting is a good thing - keep in mind that 5 watts is 5 watts or 50 watts x 4 bulbs is 200 watts - the intesity doesn't change. What does is Lighting spectrum or range. 10,000 kelvin (K) is a great range for natural ( what you see at 12 o'clock out your front door ) sunlight coloration and 420/460 nanometers (NM) of actinic lighting gives deeper penetration of the Blue band - very helpful in growing Zooxanthellae Algae (what hard corals, clams, etc.. produce as their food). I know Stoney coral enthusiests that argue T-5 HO is the best while others boost Blue Metal Halides and micro reefers whom sware by LEDS - piont being theres no absolute correct answer, we have multiple viable options.
I can't speak for everyone as we all have our own opinions on lighting - Mine goes like this - I have fish in with my corals (softies, deepwater, stonies) actinic lighting alone @ 260 watts would be great for my corals both coloration and health however it does not give a great look for my fish so I run a combined 10,000K sunlight with 420/460 nm to achieve health and desired coloration. My choice in lighting system was 4 pin 4 Bulb Power compact w/ LEDS.
