Critical Cure CBD

I cranked up the root stimulant and added 2ml/l of grow nutrients to their feed on Day 22, each one getting 500ml. They look good, a couple of slight mutations on Amelia but certainly nothing I'm concerned about. Carrie started getting some yellowing around the edges of a couple of her upper leaves which may be a response to the change in nutrients. Day 23 and I'm starting to notice a very slight clawing on both plants - must be the high nitrogen in the feed. Watered each plant with 250ml of RO water with just the root stimulant on Day 24. Might leave off the grow nutrients because I think the soil is hot enough for them for the time being. Both girls look healthy on Day 25 and are ready for the snip. Amelia has been topped, and Carrie FIMed, just above the 5th node. First time using either of these techniques (as this is my first grow). I'm happy with the topping but have no idea about the FIMing - I think I got it in the right place but I guess only time will tell. Left the girls to their own thing on Day 26 but started noticing some slight colour changes on some of the higher fan leaves and a slightly more pronounced clawing. Little disconcerting but I'll give them a day to sort themselves out. Haver moved the lights up a bit to account for the rapid vertical growth in both plants - could it be light stress? Day 27 and at first glance the plants both look healthy but the colouring and clawing has got a bit more noticeable. I'm not panicking just yet. Decided to give them a good watering with 1 litre of plain RO tap water until runoff. I'm getting a TDS reading of 330ppm which to my understanding seems little bit low. Could I have a deficiency of nutrients - is that what's causing the discolouration and clawing? Raised the LEDs to 24 inches because I suppose it could be burn from them. Day 27 UPDATE. My soil had turned hydrophobic! Rookie error. Turns out I'd let the soil dry out too much and it wasn't holding much at all. Whenever I watered it there was always a good amount of runoff, which I mistakenly assumed meant I'd watered enough. No, it was just running down a couple of channels in the soil and pissing straight out the bottom, hence why my TDS was 330ppm. No matter how much I tried to water the top of the soil it kept refusing to take on water so I resorted to slightly more drastic action - I gave them a bath. The bath was filled so the bottom half of the fabric pots were half covered, then left them there for 15 minutes to wick water up. Seemed to do the trick and now all the soil is wet through. I let them stand for a bit to drain any excess water out and took some more readings of the runoff. pH was 6.6 and TDS 1300ppm, which sounds a lot more like what I was expecting, even if the TDS is higher than I'd like. They're back in the tent now and hopefully this will help with future watering even if it doesn't solve the problem causing the leaves to yellow. Bit of a disappointing end to the week. A couple of large fan leaves lower down are really struggling after the soaking I gave them. I don't think it's so much that they didn't appreciate the watering, but I foolishly just plonked them back on the flat base of the tent and left them for the day. The bases of the pots were very damp when I got back at the end of the day with nowhere to drain to. Have built a raised mesh floor now to see if I can get a bit of aeration underneath and allow it to properly drain. No way those leaves are going to recover, but on a positive note the rest of the plant growth looks good.