It's possible you didn't install something correctly. I once failed to properly install the air relief strainer on the center pipe and turned my pool into a snow globe. Which filter do you have?
It's a Pentair FNS Plus 60. The grids all looked fine and I was careful to reassemble everything tight, or so I thought. I will try muriatic acid on it tomorrow to see if it's scale. Funny thing is this happened when I first used the Dolphin in February, about 6 months after I bought the pool/house. The basket caught a lot of white sediment several times, which gradually decreased and eventually stopped. I haven't seen this for months, until I cleaned the filter and recharged it. Also, this sediment is heavy, i.e. not suspended....the water is clear....the Dolphin is picking this up off the bottom and/or sides. Also, it's very gritty, like sand.
Today I dropped some muriatic acid on the sediment and it reacted big time...fizzed and bubbled. So I guess it's calcium. I'm stumped as to why it suddenly appeared. So far the Dolphin has probably captured two cups of sediment or more....it appears to be decreasing now.
The SWG was recently installed, which prompted the filter cleaning because I wanted to start with a clean system. Also, the pool has done this before so I think we can rule out the SWG being the source. OTOH, the Ph has been creeping up badly during the summer and I haven't checked it daily since installing the SWG to manage the chlorine, so the Ph has hit 8 periodically and I've been adding acid probably twice a week so it hasn't stayed high a long time. And this calcium sediment hit suddenly, like over night. I last added acid two days ago when it read 8.0. I aim for 7.4 and when I tested last night that's what it was. The TA is low though, at 50, so today I'm adding baking soda to bring that up. Maybe that's why the acid was bouncing?
Thanks for looking. It is a mystery. My Ph tends to rise and the CH tends to fall because our water district removes calcium. I recently tested the fill water for the first time and the result was 70 ppm. Since buying the pool a year ago I've had to add calcium to keep the CH in the recommended range. Could there be a tiny bit of calcium in the salt? I put in about 700 lbs of Diamond Crystal salt just before this started.