Filter tank transformation method and filter tank

The embodiment of the invention provides a filter tank transformation method and a filter tank, the method is applied to transformation of a siphon filter tank, and the siphon filter tank comprises a central water channel for conveying clear water to the downstream; a central water channel of the siphon filter tank is removed, an H-shaped groove is built at the position where the central water channel is removed, the H-shaped groove comprises a water and gas distribution area, and the water and gas distribution area is communicated with a bottom clear water area of the siphon filter tank and is suitable for conducting backwashing water and backwashing gas to the bottom clear water area in the backwashing stage so as to carry out backwashing on a filter material layer of the siphon filter tank; a backwashing fan is additionally arranged in the siphon filter tank, a backwashing gas pipe of the backwashing fan penetrates through a water and gas distribution area partition plate of the H-shaped groove to be conne