They had previously digested 10 liters of energy water which they used to practice for 3 days previously. So in total, they have taken 100 liters of energy water since they became godclads.
20 units of spiritual power is the limit of rank 1 because it is the maximum amount of power that their souls can possess under the suppression of the rank 1 divine flesh. Any more spiritual power and it will become too much for the divine flesh, so their spirit will begin to leak out of their body into the world.
The divine flesh is a burden to them as well as a stopper or seal on their spiritual power. If the seal becomes too weak or the pressure within the bottle becomes too high, whatever is in the bottle will spill out. That is not a good thing.
