The 4 Indigo clones stems should be touching the water, removing some leaf mass like cutting them to half size or 1/3 of the tips off will slow their transpiration.
While they don't have a root system to keep water up, or as they are not in a 80%+ RH environment where air is already saturated with water molecules and they can't release much water anyways
Slows down the rate the water is breathed out through their leafs.
Hung the fuck over my brain no worky.