Directly killing the red tide organisms by chemicals (mainly cupric sulfate, sodium hypochlorite, hydrogen peroxide, some organic compounds, etc.) has advantages of rapid effect and simplicity for use, but entails problems of high cost, pollution and temporality of control.

Precipitating the red tide organisms (by chemicals such as inorganic coagulants, surfactant and polymer coagulants) is very effective against blooming red tide, but is still too expensive for wide areas.

Comparatively speaking, the most advantageous and practical method is to use natural minerals such as clays to flocculate the red tide organisms, because there is abundant source material and the method is non-pollutive. So it is seriouly developed and applied.