I'm considering 2 x 70W MH for a 4x2x2 (400l, 120gal)
I'd be replacing 216W HOT5 with 140W MH.
My thoughts on why to choose 2 x70W over 2 x 150W MH are:
1) Not using CO2. Temp 20C
2) I want the lights on a bit longer for my enjoyment - say 10-12hrs a day.
3) Currently using 216W of HOT5 for 8hrs and its about right - 300W MH will be too much for sure.
4) There are no carpeting plants in the tank. Plants are mainly giant val, ludwigia and various potamogetons.
I'm only considering the change from HOT5 to MH for the aesthetics. I like open-top tanks and free access to view from the top. The T5 fittings get in the way.
Does anyone think 2 x 70W without suplementary lighting will be too dim?
Does anyone have a photo of their 2' high tank lit by 70W halides and nothing else?
Opinions?
Journal for this tank:
'The Snag'