25% but remember I have this dialed in 1880ppm co2, great oscillating fans recirculating it from the floor, mixed spectrum lighting with a mover. Lanky strains need more LST to fulfill yeilds better than average. Like OG's etc. This isn't for everyone as you need digital timers to "fix" the times or ou'll be getting up at all hours. This is what I did back then not reccomended, lol. All strains have different "dark" trigger times so some may start bloom cycles at 13.2 hours and some more some less. To gauge your strains tiome set time back from 14.5 after two weeks (ou must NOT start plants that were in over 18 hours as they will go automatically) I like to back down to 17 or 16 before going into this "dark" trigger time search. Do the time back 30 minutes every week look for any sign of sex once seen mark that time.
From there on you can use "that" time to trigger bloom instead of arbitrary 12/12. Now on "Time Shifting" I was trying to get plants to finish in less time then the seed companys stated and wanted to lower my electric bills, lol.
BTW you can run Mothers on 4 on 8 off, 4 on 8 off to save juice without starting bloom, thats only 8 hours lites on but still veggin!! Late!!!Bad...