it did not get as much light as it should have. If I were to do it again I would give at least 20 gallons and see what one would do.
They definitely want more light, and no outside auto will ever do as well as one under 20/4 lighting. I am experimenting this year with starting them under 20/4 and then transferring them to natural light at (approximately) 13/4 hours daylight. But, the sun clocks during the day and exposure changes so you never really get the "full" daylight...but there is something really beautiful about a plant basking in the sun
All autos operate on an internal clock, and generally they do not veg long enough to even max out a 10 gallon yet alone anything bigger. 7/10 gallon is their sweet spot (imho).