Billy's First Autoflowers

whoa, week five!? time simultaneously flies and passes so so slowly. I've installed air filtration in the nick o' time with pistils appearing on two plants now. Vivosun 4", carbon filter plus 190 CFM inline fan with no adjustable speed. Filter is hanging inside the tent, fan is outside tent bolted to a ceiling stud and currently just venting into the room. it's in a straight line with a window leading outside and in the long-term I'm planning on venting everything out through there. The temp and humidity fluctuations are GONE - which I guess makes sense since it's just circulating air throughout the room. I measured my light today and realized it's much closer to the top of the canopy than I thought (this just in: men tend to overestimate the size of things when eyeballing). Is the yellowing under the blurple real? Is the light too close? I've noticed some purples on the petioles of the Lemon Drop. Is this showing a nitrogen deficiency? Girls are all over the map in thirstiness but it's as low as 2.5 L every other day and as high as 3 L a day. There's probably some merit in growing multiple plants of the same strain rather than a shotgun blast of random strains with varying needs eh. Some rambling on lights and expansion: I've been putting in and taking out extra lights, fiddling with too many settings at once to get any consistent kinda data. I gave away the smaller EECCO blurple to set up another grow. I'm up in the air between ordering another KingLED 1500 for this tent (matching lights, each would be responsible for a 2x3 footprint) or ordering the Mars Hydro TS 1000 and using it as the primary light in here and supplementing it with the kingLED. I guess my thinking is if I put in another King, this tent will be a "finished" build with lights, air and filtration... and with flowering just getting rolling, now is the time to crank up the light intensity right? Then, when I muster up the resources in a few months, I can order a KingBrite QB from overseas, get a second tent, and drop in a DWC and have a whole second system. If I get a Mars Hydro TS1000 now, I can get another TS1000 in a month or two, replace the KingLED with it to finish this tent, and move the KingLED to a smaller tent or use it to grow vegetables or something. At $200 CDN and 260w, the Mars Hydro TS1000 and the KingLED 1500 basically cost the same and deliver in the same amount of time... Input requested, plz.