I've been watching this biopellet thing with an eagle eye. I wanted to see something happen in a tank, before jumping on the band wagon. Seaside in HB, has a display tank that runs SWC biopellets. Jayson at Seaside, tests weekly and has gotten good results. It took about 1 and a half months till the tank went to nearly 0 nitrates and phosphates. Go in and see what he has to say about them.
After seeing his success, I decided to use them too. My tank is a neglected 180 thats been running for about 6 years. After 3-4 days I had the bacteria bloom that is common. Skimmer skimmed very wet during days 3-6. Now the skimmer is skimming like crazy. About 10 days into it, the water is amazing clear. Green Hair Algae is starting to die off. I'm a believer.