can't figure this out I've tried everything!!! I think?

how's everybody doing out there? this is my first thread on roll it up, so thank you for everybody's time.

the garden

8"-13"-9"

4 1000 Watt

4 4x4 tray

median hydroton

system drip (feeding 10 on off 25)

week 4 of flowering

humidity 33%

temperature 82

reservoir temperature 23 C

PPM 1450

pH 6.0-6.2

12 plants 2 trays

using Fox farm nutrients and bloom enhancers plus floral nectar and Cal Mag.
is what I use and have used for my last two harvests in this garden.

so at first I thought the roots were locked up and they weren't observing magnesium and potassium. so I flushed them for a day and a half and added back in my nutrients at a lower PPM. I did not see any change within two days, and the problem seemed to get worse. so then I thought maybe a nitrogen deficiency but isn't that weird to have an nitrogen deficiency in week four flowering? so
one of my buddies also told me that he thought it was a mold problem so i sprayed two days ago. and again no improvement
I also started using a reverse osmosis machine so I don't know if that has anything to do with it?
I don't know any help appreciated

Well let me be the first to +rep you for the nice setup. Second. I doubt you would see changes that quickly. 2 days is asking alot. And having a nitrogen dificiency or better yet lack of nitrogen during week 4 is not abnormal. Whats your NPK? more than likely while switching to bloom nutes it will seem as if your plants fade to a lighter green. Thats normal. Then again you said you used the same nutes last time. May I ask if the nutes you are using are the same jugs from the previous grows. Ive had nutes sit for 6 months (down fall of buying bulk) and if you dont shake the shit out of em they can really mess with your plants brotha. But all in all everything looks good, just maybe flush one more time and go back to nutes. Even add a bit more N to your doses

we have the same problem

if your water had a high ppm before you switched to ro it may change your food levels by 1/3rd to a 1/2 depending on what your previous water was,make sure that your food has all the required nutes,i always mix 2 litres of tap water with 10 liters of ro,i dont know why but it seems to help,but then i didnt do any scientific study.