Keep one tube empty
An empty tube is the most valuable space in Water Sort Puzzle. It gives you a buffer for moving colors out of crowded tubes and prevents the board from locking too early.
Before making several small pours, ask whether the move helps free a tube. If it only shifts the same problem to another place, wait for a better sequence.
Work from trapped bottom colors
Look at the lowest visible layers first. A color trapped at the bottom of a full tube usually determines the moves you need to make next.
Clear the colors above it step by step, then merge that bottom color with the same color in another tube.
Avoid mixing too many partial stacks
Partial stacks are useful, but too many of them reduce your options. Try to complete one color group before opening several new groups at the same time.
If a level feels stuck, reset your plan around the empty tube and the most blocked bottom color.