I would steer clear of hydrogen peroxide while adding oxygen and killing bacteria it also kills any good bacteria you have in there from your nutrients, add some more air stones if you want more oxygen in the water, also try getting some hygrozyme it will kill the brown slime on the roots. As for keepin it colder well, i've got a gh waterfarm under a scrog right now with a blackstar and a single h150 magenta kessil in a 2x3 box with an agent orange in it. Its growin excellent i cant check my roots because im well into the screen now in the third week of veg but im about to flip the switch in a few days. Your fan problem isnt that big of a deal, look for a container with a 3 inch diameter (i assume your inline was a 4 inch like my 235cfm was) get a 4inch to 3inch pvc step down, some metal ducting, some tape, and some muffler packing, fiberglass etc. something of that nature. You drill holes in your small container and cut off the big end wrap it in a screen shove it on the step down, slide this inside the ducting the pack around your 3inch pipe with the muffler packing. Bam you just made yourself a muffler. Now that was the quick way to explain it but its quite easy, you can do the same thing with activated carbon on the other side so you have filter action if you want or you can run dual mufflers.
How often do you change your rez, I change aproximately every 3-4 days after i've added 2 gallons of fresh ph'd water. So i know theres no nuts in it and essentially give it a quick flush overnight and then drain that and add nutrients again. I've had good luck with that.
Interesting to see someone else growing this strain in some form of hydro i havent seen many, i had bad luck with nirvanas black jack. All mine hermed to some degree, and the other plants i had growin right with em on my ebb and flow table didnt =(. Im still growin out a blackberry kush and a wonder woman from them. I've got hopes for the wonder woman the blackberry has me a bit scared right now 1 seed out of 40 or so i planted lived and it happened to be female lol. Crap seed batch i got unfortunately. Im waiting to try this pineapple express, og 18 and moby dick i just got from attitude. Keep growin man black jack looks nice. I liked the way it looked in veg always chunky
