Well, it's a 2 1/2 HP pump, and the pool guy which set it up seemed to think the pressure was okay but even assuming for a minute the gauge itself is inaccurate it wouldn't negate the fact that it suddenly read about half of what it read previous.

I haven't checked the basket yet (will tomorrow morning -- was too busy tonight) but otherwise I'm not sure what could be going on. Everything else (infloor cleaning, skimmer, spa) seems to be working fine.