Tips of leaves are yellowing

Hello riu I have a diy fogponics in a 4'×5'×2' tent have a 8" fan blowing new air into tent through a vent in the bottom of one of the sides and a 22" carbon scrubber linked to a 6" inline fan pushing out old air as far as air circulation inside the tent I had 1×6" 2 speed fan but a month ago put in this weak 1' fan didn't think it was sufficient enough so a couple of days ago I put in another 6" 2 speed fan and got all the leaves to move. My Light is a 150w HPS with an open reflector. As far as nutrients i be been using heavy 16 (not fire just the original) and a couple of days ago started using bud candy. I know way late but better late then never.( Plus I'm on a low budget)I use the usual general hydroponics PH set of PH up, PH down and the testing solutions. I have been using the Scr.O.G. technique. I have been thinning out the canopy to keep airflow through the canopy optimal. I lollipopped about a week ago.(couldn't get myself to cut them until then) I have not flushed the system so there is a possibility of nut. lock. I changed nutrients every other week during the veg using the lowest amount recommended in flowering I had to start every week because of the water level getting to low also using the lowest recommended amount. I was wondering if there was anything I can do to make this a more efficient system and if there is anything I can do next grow to gain a larger yeild? Thank you for all your help in advance.
T.I.

I wouldn't recommend cutting/defoliating after you start flowering, the plant wastes it energy repairing itself instead of using the energy to produce flowers. BTW nite lockout is more common when you don't flush because excess salts buildup and throws nite levels and pH outta whack

PropertyoftheUS so no defoiling once put in 12/12 cycle. The only reason I did was I had poor air circulation and had no money to get another fan. Do you think I should get another 6" fan and replace the shitty 12"? Like I said I'm on a budget so I don't want to if I don't have to. And how can you tell if you have nut. Lock? And what would be a good in-between flush I already have final phase from av. Thank you for everything in advance