Yesterday, when the filter pump of my pool started in the morning, I noticed that the water was not circulating in the pool. There was no water coming out of any jets and the pressure on the DE filter was at zero. I put it in spa mode and the water came out in spurts and started circulating. I put it in filter mode, nothing. I repeated the above steps and and on the second try, water came out in spurts through the pool jets and started circulating.

Same thing this morning.

I notice that there are bubbles coming out of two of the pool jets. Pressure is fine.

The filter pump and DE filter are about 16 years old.The filter was opened up and cleaned only recently.

What do you think the problem might be?