I've had a Jandy Stealth 2.5 HP pump for about 8 years, which is rarely used (used for spa jets only, no recirculation/etc -- about 10 hours a month usage).
Recently, I noticed the output decreased significantly, and there seems to be a little air coming out along with the water from the jets.
I went to the pump and noticed that it's not filling the basket completely. In the past, it worked just like any other pump. That is to say that once it was primed, the basket was filled full as it pumped.
It's not making any odd noises, it does not sound like it's laboring or having any issues with the pump or motor. I thought it might be getting air somehow, but if it were, it would be difficult to locate as the pipes are entirely underground, start-to-end (excluding the last 2' into the pump).
Does anyone have any ideas what would be the most common reason for this, or how I should begin to diagnose?
Thank you in advance