What kinds of swimming pool filtration equipment are there?

Traditionally, there are quartz sand filters, which are commonly used, and diatomite, but diatomite seems to be not used much. I have also seen private swimming pools, which are integrated and convenient. I think the equipment is also quite simple. According to my friend, the effect is good. I used it all summer this year, and there was no problem. It seems to be recommended by a friend of his in Shenzhen, and it is also very cheap. What brand does it seem to be called? You can search online, I hope it will be useful to you.