leaves showing problems my water quality was shocking using ro water now as was shockingly bad 8ph and stupid ppm

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Calcium, phosphorous and potassium deficiencies.

I had a look at your diary and it hasn't been updated for a bit so your further into flower then your diary says. My opinion is she looks a little stressed from some possible environmental factor, either too bright a light or light on to long or to close. Or temp/RH maybe causing some issue. Also you should be on a flower nutrient schedule by now, so in veg you would have had a ratio 3-1-2 or 3-2-1 for NPK and in flower the ratio would be 1-2-3 or 1-3-2. I try and get a 3-1-2 ratio for veg and 1-2-3 for flower.

it can be hard to diagnose a plant without a picture of the whole plant. Many deficiencies have very similar looking beginnings. Some start low on the plant, some high, some new growth and some old. Phosphorous would be accompanied by dark leaves usually discoloration starts on lower older leaves, Potassium is more likely the culprit. Phosphorous may be lacking too with the purple stems but plants can do that in flower stage naturally. Make sure lights and power is right, humidity is high, during flower between 40-60%. I stay around 50% myself, verify PH and watering habits are good

It will almost certainly be lack of P Phosphorus and K Potassium.They use a lot more P and K during flower especially mid flower and will take it out of the leaves. Lack of K shows with yellow edges. With living soil you're best off with guano thats high in P Phosphorus and Ash that's high in K Potassium.Any shit will do and any hard wood ash will do. I actually bought some Guanokalong Palm Tree Ash.1 heaped table spoon every 2wks.Iv been using guano and ash on either side of using Advanced Nutrients Big Bud for years and it works really well. Guano is around 15% P depending on the type and ash is around 30%.Thats a high percentage but its organic so shouldnt burn unless you really go over board.The leaves are also cupping in the last picture so shes not liking the lights. Too close, too hot,too bright?