Can't seem to sort the deficiency

There are about 3 weeks left in flower now on my plant and I can't seem to get the nutrients/PH/what? sorted.

My leaves have what looks like a copper deficiency, but likely it's more than this.

Currently growing in soil, with some natural long term fertilizer (organic Tomato fertilizer with sheeps wool) in the soil I added at week 4. I got a PH and PPM tester so have been doing this. The water from the tap comes out at 8.2PH, which is very high, so I found I needed to lower the PH a bit. Once I got the PH tester I watered and tested the runoff and saw the PH was around 7.5. So my goal began how to get the PH down so that the run off is around 6.5.

I started to drop the PH of the water using sulfuric acid and testing the runoff. I ended up needing to drop the PH of the fertilized water to PH of 2 (!!!!) in order to get the runoff to be in the mid 6 range. I've tested this many times, thinking the PH much be too low, but the runoff looks good now. My best guess is the fertilizer I added is raising the PH since it's an organic fertilizer.

I've gone through a big flush (60l) drained through to hopefully clear off any residual leftovers or salt buildup and now about 2.5 weeks later, I'm in the same place as before, the leaves aren't recovering and slowly getting worse.

I can flush again, but I'm unhappy with needing to PH down the water so much, it feels wrong that 2PH goes in and 6.3ph comes out.

I tested the PPM before I did the PH down, and it was at 1400, but it jumped over 2k afterwards, due to the sulfur I 'm guessing.