More weight.

Hello

New to th site, but not new to the herb. I have been growing for a few years and have been getting better and better with what I have. Right now inside a 10x10 room that is 8ft high I am running 25, 2 gallon multiflo buckets under 3k of hps. That would be 3 1k hps. non-aircooled rectangular reflectors. The room is not sealed, as i do have an exhaust fan, however 75% of the time it is not turned on, only during the late flowering stage. I run Co2 via bottles during lights on. Outside the room the air is scrubbed with a bigass carbon filter (cant remember the name) room is kept cool with ac at a temp of 82 degs lights on, and 72 lights off. 55 gallon res is kept at 65 with dual chillers. strains are serious seeds white russain and chronic. vegged for 4 weeks or until 15inches tall then flipped. end up at an avg of 40inches tall and give an avg of 65onions per room cycle. feed gh nutes with koolbloom, and gravity as extra's late in flowering. I see folks pulling in more all the time and I'd like to get up there, any advice?

As a sidenote I am very happy with the produce. Smells great, looks great, knockout stone from big dense buds, just not enough of it.

how is the canopy? is it even throughout? You said your room is open right. Doesn't the c02 get out if it is not sealed? genetics are the most important part. Maybe you don't have a high yielding strain. I have never grown those two so I am not sure.
fan for air movement?
You seem to know a lot and have everything under control.
Maybe switching to different nutes might help or adding to them.Scrog? How do the roots look? do you need a bigger vesicle? What are your grams/watt?

Bump your res temp up oh so slightly.
Lights can go on a mover on the 'sun circle' style, or on 3 individual rail type movers, or you could add a 4th (that would be the right lumens per square foot).
Try upgrading your lightbulbs, and if they are over ~9 months old, consider replacement.
You got air movement within the room?
What is your canopy like at different stages?
Do you have a reason for wanting large plants, such as a low plant count limit? You could shorten your room cycle by going to a SOG in 4- 4x4 trays, each under a 1kHPS, on separate res or a pair on one res flooding alternately, depending on if you want to harvest all 4 at once, 2 per month, or 1 per 2 weeks. Lots of ways to run a SOG in a big room.
What is your available veg space? Do you have a space in your flower room (hint hint, the space that doesn't yet have a HPS...) where you could stick a MH400 and use that for the plants that have JUST entered the room, all clustered under that light, to control stretch in the first 2 weeks of flower?
At the top of 'basic', there's a 'continuous canopy' sticky that is kinda interesting (although I am biased in saying that, lol!!!)
Welcome to canncom anyway!

There are four fans within the room for air movement. The co2 runs the entire time my lights are so i really do not worry about any escaping.
The canopy is even, all plants are within 4 inches of each other throughout the grow cycles. In other words they stay level at the canopy. While the russain isnt known for yeild the chronic is. Both come from selected pheno's within the strain that I liked the most. the russain pheno is big bulging buds, very little leaf, and frosted. The chronic has a touch more leaf but the cola's swell up big time adding extra weight. As I said I'm happy with the final product, but the buds could be denser and again, there just doesnt seem like im getting what the room is capable of putting out.
Last cycle got me just over a half gram per watt.
Roots look great the entire time, but by the very end they can get a touch rootbound, but not bad, and i have grow plants that were much more bound in the end.

Also I have no real reason for the bigger plants, other than I enjoy tending to the bigger plants.
Yes there is room for one more 1k however it would upset the harmoney of the room causing me to have to convert the other 3 lights into air-cooled hoods. 4k watts of uncooled hps would be to much for my current air cooling capabilities.

Also I should add I run my plants on the GH basic 3 part nutrient and go very easy on the extra's. Most of the time in veg my ec stays under 1.50 or 750ppm and in flower will not get over 1.70 or 850ppm. Should I try to run this number higher? For fear of burning I try to keep it on the low side. Also my ph is set to 5.5 and in 24hrs drift to 6.3

Damn it just keeps coming.

I guess i should also add. right now is day one flower on my latest batch. 30 2 gallon multiflo with 15 WR and 15Chronic. the clones were vegged for 30 days and are an avg of 18inches. All plants are super bushy. Also in the room are 6 soil plants that have vegged for 6 weeks, are 20inches tall, and are of unknown origin. (seeds I've had for while and lost the labels.) All look indica, and all have been sexed, and are of course female. The dirt plants are not my main concern and are left on the outskirts of the light and turned daily to ensure al around growth. Hopefully the addition of extra plants will see a gain in final weight

Half a gram per watt per harvest or per month? Per month, and that's a GREAT number.

Your pH swing looks fine; many people do that on purpose, but do you know why it shifts?

Commercial croppers will often run their ppm up in the 'scorch' range on purpose, then do a flush at the end for flavor. With CO2, you should be running your temps AND your nute strength higher than normal, so with a nute strength that is low even by non-enriched standards, you are not optimizing your enrichment.

I'd crank up your ferts until you actually SEE tip-burn, and record that number, then drop JUST to the point where it stops occurring. At the same time, bring your res to 70'F with aeration, and bring your room to the 85-90 day/75-80 night range. With added CO2, your limiting factor is not longer atmosphere; it is availability of ferts and the metabolic rate of the plant. Heat increases that rate. CAUTION, using Gravity in the higher temps is dangerous- plan to drop your temps back down into the low 70s for the week after application.

No, not every month. Thats a half gram per watt every room cycle which is on avg around 90 days.

I will adjust numbers accordingly, and hope for better results.

Any other suggestions? I'd love to hear them.