Crystal Clear does not work well if there is (too) much movement in the water, preventing binding. Too many dissolved substances in the water can also interfere with the effect. Partial water changes are a good remedy for this. For example, change 25% of the water and repeat this every 2 to 3 days (3x in total).

Against green water (floating algae), Crystal Clear is a short-term solution. The remedy binds the algae (flakes) and the water becomes clear again. However, you do not remove the cause and new algae can form again in a short time.