Keep in mind the FFOF is supposed to be all you need for a month or so. I don't have a ton of indoor experience, but using the same soil and nutrients as you. I found out that when I had two larger plants (gorilla girls were approaching 6 weeks and seemed to have slowed down) getting into that time frame I used about 1/3 strength to be sure. They're in 3gal bags. At that time I had another, bagseed, about 3.5 weeks behind. It is in a 5 gal bag. Any residual water solution after good application on the first two was given to the third one. When I saw all of them perk up (didn't look bad prior but it was noticeable) I realized it was all dependent on strain, temp and humidity. This established a base, for me, to begin tweaking upward until slight tip burn and dial it back just a bit and monitor. I don't do a large nute and water only cycle. I try to keep feeding the soil by using 1/3 to 1/2 strength every time and be sure I get a good dry off in between doses. The first month with OF was pH'd water only and no runoff to use up what the soil offered. When I started the nutrients I started watering to slight runoff initially and then built up over a few cycles to a more proper runoff and monitored pH closely. It took several watering cycles to get the pH where I wanted and the plants seem to agree. Now they're demanding more frequent applications as the pots are dry every few days. No schedule now, only what they tell me they need.
