Quick One from RQS - First Grow

Everything is going smootly,, the tent is starting to get crowded. I'm trying to get everything tidy by tucking branches under the net as they grow. The smell is present, but muted, it doesn't smell like cannabis yet. I always thought of a Gallon to roughly be 5 Litres. But I just learned that 1 Gal can either be, 4.5, 4.4 or 3.7 Litres ... among other things.