Yellowing from the bottom up

I’m already 4 days into week 4 and this started happening i only use 1 5 gal bucket and wait till she damnnear drinks it all then make new solution and add roots look super healthy just very very full.

Have you done a res change? I just finished an experimental grow in a DWC. You may have a salt build up on the roots, just dump the res and start with a fresh batch of slightly weaker nutrients. But that's only if your 100% sure your pH is on point and you if you stopped feeding grow nutrients to early that will do it too. I found out DWC needs a couple weeks ( 2 weeks into flowering give grow, then switch to 50/50 grow/bloom, then after stretch is done full bloom ) of mixed nutrients. My OG Diesel Kush autoflower got yellow at one point and I did a res change and added more grow nutrients. Check out my OG Diesel Kush autoflower diary. I only did 1 res change the entire grow. I don't reccomend that tho. I was attempting the lazy man DWC grow.