strain

Here is what I do with great results.

Weeks 1-2 temp 80-83 with c02 1350ppm and RH of 55% Lights off temp: 75-78
Weeks 3-7 temp 78 RH 55% co2: 1350 Lights off temp: 75
Weeks 8-9 temps 73 RH 35% co2: 700 Lights off temp: 73 (c02 stays off) Allows buds to get dense and color is developed.

Make sure that they are getting fully saturated. Runoff is good especially with the higher temps. Remember: plants love plain fresh water at least once a week also. Try to keep your day and night temps within 10 degrees. Heat will speed up their metabolism and you should try to warm things up a little with c02. Its the end of flower when we want the buds to fill in dense so we drop the temp down and taper off of c02.

If you're not hitting the numbers you'd like I'm with soda on this one. Probably your strain if you're monocropping. I'd also be curious as to quality of your veg time as your flowering room seems on point (veg lights, spacing, pruning, etc). With all that being said, I'd point to desert squirrels discovery of house and gardens lack of phosphorus for sufficient rooting for larger plants. A weak root mass for a huge plant up top is going to translate to an inefficient pathway for nutes to be providing your bushes with large yields.

Are you having deficiencies?

i would cut the numbers down. It sounds like those plants are crowded in that room. I run a similar setup to that with the mag's and #7 SP. I run 2 tree's per 1k though. if you are running 4.25 tree's per light they are crammed together so you dont get any light penetration through the canopy.

Room temps a little low for co2, I would try and hit 82-84 with lights on, night time temps look good, rh looks good...are you hand watering or using a drip system with sprayers or emitters? smart pots on tables or seperate on the floor with catch trays under each of them? what other ammends do you run..Amino, drip clean, top booster, budXL, shooting powder, roots exelerator, algen, etc.. ?

to hit decent numbers alot goes into the veg. you have to make sure to take a few more cuts then you need everything has to be transplanted or uppotted at the same time. None of this ill do soem today and finish the rest tomorrow, as well as topping. Alot of people think they can just throw up a bunch of 1ks and hit numbers without proper veg rooms. its the biggest mistake i see in so many rooms. I walk into a room and theres 6 1k's for bloom and for veg is a T5 and and a few 600's.

Go down to smaller pots (5gals)6 weeks probably isn't filling those 7 gals. Make sure to up pot and not just go into the biggest pot you have. 5x5 to 1 gal to 3 gal to 5 gal or at the very least 5x5 to 2 gal to 5 gal. topping and training your plants as needed in between. Dont worry about CO2 until your hitting 1.5 or more a light because its not really helping right now. Take 22-24 cuts instead of 18 and pick the best most even ones(18 or how every many you choose to run, 1 run 9 a light 6 week veg) before your 2nd up potting. We want to build and even canapy across the room. Every light should look the same. make sure to water before they dry out soon as you let plants dry out your losing yeild.you need to find a strain that can push out decent numbers. Your not gonna hit big numbers if you are battling mites or thrips, aphids powdery mildew and so on.

Tex has it right in veg i am running my room @ 84*-88* and they just blow up in the tropical climate.

Containers are over sized. Also run 1-4 per light or 9+. Anything between there is dreaded no man's land. You want plants getting rootbound ish by week 3 bloom. Everything else is fine. Can be optimized but its pointless until you get the plants right. Not the other way around.