First off, what is that laying in the sand, it looks like frogspawn or hammer maybe. Either way that needs to be picked up asap as that will cause brown jelly disease. Next I wouldn't leave the sps under pc's for very long or it will start losing color fast. Lastly, I use credit cards to scrape the hard to get to areas and the coralline algae that the magfloat seems to have trouble with. HTH