i would sya for a 20gal just get one MH (70w or 150w), and then just add actinics as well. you could do a 70W and then two T5 bulbs.
and i agree with our buddy micheal. retro-fit all the way. if i could take it all back, i would buy retrofit. without a doubt.
(zma21- power to the bimmers! M3 all the way!
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