70w or 150w MH

[geiges]

should I run a 70w or a 150w MH on my new frag tank.
the tank is 2'x2'x8"?
I will be running a 14 to 20k.

[DesertBandits]

I understand 150w has a much more developed spectrum than a 70w MH, in other words, 70MHs are just crap. Also I doubt 70w will get you a 2 foot spread.

[DarG]

The spread depends on the reflector. I would run a 150, forget the 70. Buy a good reflector, Lumenmax, Lumenarc ... and you will get full coverage. Not much variety in 70 watt and the par is really low, especially with a bluer bulb. 150 watt on only 8" deep tank should be fine with a bluer bulb. You'll get full spread without a really severe hot spot with a quality reflector like the Lumenmax or Lumenarc.

[geiges]

http://reefcentral.com/gallery/data/580/1322238FinishedReflector1.JPG

mybe a 150w and make this Reflector.
I can get a good deal on a 70w sunpod and wood be a nice all in one light.

[DarG]

Coverage is limited by those tiny reflectors on the Current USA fixtures. I owned one and I personally wouldnt use one on a tank wider than 18". The tank is 24" wide, you would get better, more uniform coverage and less of a relative hot spot with a Lumenmax or Lumenarc reflector like in your pic and a single 150 watt than using even two 70 watt's in a Sunpod.

[geiges]

Darg thanks for the input .
mybe I shoud use 175w se so all my lights are the same?

[geiges]

what are the advantages of double ended MH vs. single ended bulbs if any ?

[DarG]

In good reflectors, either will do the job just as well. The rest of it just fires up a debate that usually gets ugly. 175 in a Lumenarc or Lumenmax would work great.