While not strictly necessary, your pond can benefit from having a pump and biological filter to keep water cleaner.

虽然不是绝对必要，你可以受益于池塘有一个泵和生物过滤水保持清洁。

youdao

While not strictly necessary, your pond can benefit from having a pump and biological filter to keep water cleaner.

虽然不是绝对必要，你可以受益于池塘有一个泵和生物过滤水保持清洁。

youdao