Is this a phosphorus deficiency?

Maybe because I had bad batch of it I think. But all the tops are deff yellowish compared to fans

Hi Kush, Sorry you are having this problem. I too have what looks to be very similar to this. My plants are going on 4 weeks now. I was curious, what does the new growth look like? Looks like you are growing in a DWC bucket?? I'm growing in Coco coir 40% perlite and would like to share I am also adding calmag because it does look a little like calcium deficiency but not all signs are there, for example the new growth is growing healthy and big while the plant is turning "brown" from the bottom up. I'm giving her 2ml a feed (once a day) for the last 10 days with no signs of it getting better. Looks very much like a P deficiency to me. I seen somebody above mention using "bloom" nutes to try and correct the Phosphorus def. I have been alternating roughly every 2 days floranova grow and bloom with no signs of it getting better.

prolly a flush with good oh n I wouldn't nute for awhile feed her when she's hungry

Yes just starts with the older fan leaves I'm noticing a magnesium deficiency on new growth at the top do you guys think I'm giving to much calmag that's y it showing mg

What are the NPK ratios of your base nutes? What is your water source?

A:3-0-1 B:0-4-3 using a small boy dechlorinator

I would have to agree with what a few said earlier. Some nutrient stress along with a slight Calcium deficiency. Yes your ppms seem low for burn. A few things come to mind. The strain is nute sensitive or your pen is out of calibration.

I see a lot of burn issues misdiagnosed as deficiencies.