is not a real good measure for a reef tank. A 5ft tank is somewhat different. A MH
light normally covers 2ft of area. Most people get 2 MH
's for a 4ft tank. I almost bought a 5ft 100 gal
and plannined on using my 4ft fixture(2x250 MH
+ 2x54 T5). I know a guy that uses 2x400MH w/ VHO
actinic on a 125 and it looks nice. A 2x250 is about all I can handle on my 75 gal
due to the heat it generates.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,