If you are talking about a standard AGA hood that is only about 20watts, then your polyps will probably survive but not thrive, grow or show there best brightest coloration. When it is stated that they dont need much light it generally means they can be kept under compact flouresent(power compact) fixtures. With about 2-3 watts per gallon. Most soft corals can be kept and grown with this light and some long polyped stoney also like frogspawn and bubble coral.
Power compacts are a bit pricey but much cheaper than metal halides or T5 fixtures.