Acropower because its easier to dose. Reef roids are great but in the long run you're going to get lazy and not want to make up the mixture, turn off all your flow and feed. (that's why I have a full bottle of RR on my shelf now). If Polylab can make RR into a liquid it would be awesome. Ultimately, I wouldn't (i don't) dose any of it as I'm not so sure how much is actually consumed by our corals. (Think about it, if you broadcast feed, how much time do the corals have to cosume it before they(RR or AP) go down into the sump and skimmed out. If you target feed, please refer back to my first statement. We have big skimmers to take that stuff out the water but we are steady putting it back in and wasting $. Just my two cents.