Bubble explosion when pump turns on with solar heater

[Cabovegas]

we experience a huge explosion of bubbles when the pump turns on in the morning , this didn’t really happen during the winter when the solar was off, if this is normal I don’t mind, but don’t want anything to break. I took a video to better explain.
Solar pool bubbles
Solar pool bubbles https://youtu.be/g14UYqunXgs

 

[1poolman1]

we experience a huge explosion of bubbles when the pump turns on in the morning , this didn’t really happen during the winter when the solar was off, if this is normal I don’t mind, but don’t want anything to break. I took a video to better explain.
Solar pool bubbles
Solar pool bubbles https://youtu.be/g14UYqunXgs

Completely normal. With the solar off the panels drain and air enters from a vacuum relief somewhere in the system (usually at the top opposite the plumbing). Very similar to covering the open end of a straw and lifting the full straw from the glass, the only way the liquid will come out is if air can enter by opening the covered end. It would happen anytime the solar cycles on and off, regardless of when during the day.

Do you have an automatic solar control or is this manual? If the solar is constantly "on" it will act as a cooler if the rooftop temperature is less than that of the pool water. That's usually the case if the pump starts early in the morning before solar heat is available and the system is manual.