Gotta identify the pest and apply the proper treatment. Without positive pest identification/s, you're likely pissing in the wind.
Note that most effective options are off the table during flower.
4800 isn't really that large as things go.
DWC if done right is best for plant count restrictions. Flood n Drain SoG is best if canopy area restrictions.
GH Flora 3 Part.
Use a day night temperature controller and a dust shroom and intake cold air as required to maintain temps.
You could also pull a negative pressure on the hoods and vent that heat upstairs when lights are on.
Many commercial greenhouses that produce ornamentals, lettuce, herbs and the like use gh 3 part. It allows flexibility in feed ratios and to those that are familiar with it can achieve superior results with minimal expenditure.
All I use is gh 3 part and calimagic. A little ph down. That's...
Put the AC feed on a double pole contactor of appropriate ampacity equipped with a coil voltage compatible with your lighting controllers trigger. If your AC resumes proper operation at previous settings after a power outage, this will work. Test by tripping breaker, wait a few minutes and...
One can always run .5ml bleach sodium hypochlorite per gallon. Replace daily. Pool shock is stronger, calcium hypochlorite, if you have it.
I swear by the live res, after trying sterile for years with limited success.
By feeding soil with GH Flora, you've pretty much given up on the soils organic nature and are just using it as a medium for your hydro nutrients. Water at 5.8 if using GH Flora unless in coco (6.1)