Kurt

That was my first guess, so I purchased a new cover, but it didn't help.

I have a 1997 Discovery spa that has functioned well until recently. I found numerous plastic particles clogging the filter. Initially I thought they were styrofoam balls, but they're actually fairly uniform white plastic bowls about 1/8 in in diameter. They're source is not anything visible from the outside and the spa is not leaking. I thought it might be the plastic piping deteriorating due to excessive bromine and low PH, but it continues to produce the particles after the chemical imbalance has been fixed. Are there any internal parts of the motor, ozone etc. that would produce these type of materials? Any ideas?