While not blocking as much water as completely closed does, partially closed/open allows some water to flow over the triple floodgate while still keeping a depth of (2.0) tiles deep of water blocked. Setting the triple floodgate to ( 2.0) will adjust the height of the triple floodgate to (2.0) tiles tall. While not blocking as much water as completely closed does, partially closed/open allows some water to flow over the triple floodgate while still keeping a depth of (2.5) tiles deep of water blocked. Setting the triple floodgate to ( 2.5) will adjust the height of the triple floodgate to (2.5) tiles tall. Since a triple floodgate is, at maximum height, (3) tiles tall it will block a depth of (3.0) tiles deep of water. The triple floodgate will block the most water it can.
Setting triple floodgate to ( 3.0) will adjust the height of the triple floodgate to (3.0) tiles tall and will completely shut the triple floodgate. The option a player will choose to implement at any given time will depend purely upon the situation they find themselves in at that time. There is no single absolutely always correct answer. Which adjustment option to use, at a given time, will depend upon various factors, none of which are under the control of the player. The triple floodgate has (7) adjustment options. The range of adjustment for the triple floodgate is (3) tiles.