Hey buddy, just caught my eye you're using Sunshine #4. Imo, it holds waaay too much water. Be wary of over-watering! I switched to Rainforest blend because it drains so well...
I've heard a million things about soil grows lol but this is what works for me. I fertilize every other day with half-strength nutrients, and give plain water the other days. I flush before transition (less stretch) and before taking cuttings. I use water only the last 10 days or so. Never have problems with nute burn, root rot, or soil chemistry if you are consistent and err on the side of 'less' when it comes to nutes.
If you're using RO water, don't worry about checking pH (IMOO!) because the nutrients are pH balanced and as soon as you add them the water takes on their value. If using tap water you will need pH down. I use tap water and pH my nutrient solution to 5.8. I wouldn't worry about TDS or EC at all.
p.s. use 5 gallon pots!