Check out a vpd chart your in the red with those numbers I'm quite sure that's a big part of your problem. Obviously depending on strain and certain growers can manipulate these numbers but most of the charts are good to follow.
Lights off is usually not really a problem as much as lights left on. I've literally made the exact mistake and lights were out for 3 ish days. No harm done. No hermies. Its when you leave the lights on that stresses them out.
I got that information from a thread on here.
It's something to work off of I'm not saying these numbers are 100% correct. Obviously there are many factors involved. Here take a look if interested.
https://www.rollitup.org/t/pot-size-to-yield-ratio.700361/
Before trying all those lotions and potions just go get a bottle of tomato nutrients from pretty much any shop. Will see you through this one, then check out buildasoil or something like that
I've personally done 16/8 with no problems, only 2 or 3 grows tho so dunno you might run into problems with certain strains, I've also done 18/6 and 24/7 and between 18/6 and 16/8 I didn't notice too much but 24/7 they imo grew faster. Just my 2 cents