Not to discredit or argue with the previous answers but I'm not sure they are offering the best advice for your given situation. Blindly saying you need a bigger light, more wattage, ect. doesn't make sense. No target goals have been established so how can we say this light is good/not good enough? I'm assuming you're a newer hobbyist and aren't shooting for a SPS tank. If that's the case, this light is plenty for lower light corals and LPS. 100W on a 29 gallon tank is ridiculous, PAR wise you'll want an even blanket of light around 100-50 PAR. A few spots higher (180-150PAR) wont hurt anything either if LPS is your goal. Wattage might be one measure of the power of a light but it's not accurate. There are LED lenses, LED separation, LED quality, and other factors that come into play that affect PAR output of a light. The ONLY correct way to know if this light has enough power is to do your own PAR testing in your tank. If that isn't something you're willing to do, then it comes down to using what information we do know about the light to make an educated guess and from there trial and error. A wider light WILL help spread the light to the ends, but depending on your rockwork, may not make any difference either, so use your best judgement there.