Both valid points. But part of the reason I'm tempted to try this stems from the recent research that indicates that the bacterial growth itself is used as a food source for some types of coral...as much or more so than the microfauna we typically associate with coral food! Also, I don't think carbon dosing or biopellets are ever going to produce the true "ULN" system that SPS keepers try to achieve. At best, biopellets in conjunction with macroalgae (I have C. racemosa and C. taxifolia in my tank) may just offset the heavy feeding and excess waste that is usually involved in seahorse aquariums.
If this tank had no coral whatsoever, I would probably consider a pure macroalgae tank and let the stuff run wild. In fact that IS the general plan when I set up my pipefish tank. But since this tank has a combination of polyps, corallimorphs, soft corals, select LPS and even a rogue Montipora in it, I don't want the macroalgae growing willy-nilly all over the rock. I'm looking for another form of nutrient export precisely because I keep the macros trimmed back, and the bioplastics look like an interesting way of doing the job.
Nike, this is for an existing tank BTW. I don't know if you've ever seen it if you're not in the seahorse forum too much, but
this is the tank in question. Tank's been running for 15 months, seahorse has been in for 8.
Back to the original question....I wish someone who HAS used this could chime in -- I'd love to hear some more reports about the effectiveness of the product and the amount of time involved in seeing any effects!