I don't know what are the "best" but we just got a bunch of samples from reef nutrition and the "trigger pods" are pretty awesome. I guess all kinds of things eat them and they are alive so they reproduce like crazy in you tank and you don't have to keep adding them all the time. I observed that they maybe more effective if you have little or no mechanical filtration, ie if you are using reactors, filter socks, or sponges, I think they get hung up in there and die. I added half to my 150's new fuge and the next day when I went to change out the filter sock there were a ton of "red" dots. I added more now that my water is clear and don't have the sock on now so maybe they can hang out and reproduce in my fuge and rocks ect. Here's a link to reef nutrition, they have a lot of good info on there! Reef Nurtition
Hope this helps!
Heidi