Should EC be higher than TDS?

I typed up a long reply but lost it so here’s a quick 1 :) It looks like you may have early stages of root rot. The rising PH, roots don’t look white they look like they’re starting to brown. Your best bet is to go sterile at this point. You could try to fight the battle with beneficials but it’s easier if you don’t have them to hand to save the plant by using sterile system H2o2 bath of the roots wash them vigorously in a 1/3 part h202 bath. Clean the res using h202 then continue with adding 5-10ml/Gal to maintain sterility you will need to add it every 2-3 days. You can also use Calcium Hydrochloride which is another preferred anti microbial. When running sterile you can forget beneficial microbes in the res however you can still apply them as a foliar including kelp which is great for sick plants. If your roots smell at all earthy then that’s just the start the plant will wilt then the roots will start to smell eggy it happens very rapidly. Message me if I’m wrong and I can help you with your EC confusion. 🤞 good luck

"I'm trying to figure out is the EC should be higher or the TDS. " EC and TDS are fundamentally different things; TDS measures total dissolved solids regardless of their charge. EC is always lower than TDS in numeric value; EC readings avoid conversion inaccuracies; it is recommended to measure nutrients primarily in mS/cm rather than relying on converted TDS ppm. Calcium conducts significantly better, and magnesium conducts slightly better than both iron and zinc. Organic matter will read on a TDS but not on EC until it's broken down. EC is the fundamental driver of osmosis; it's not just some metric made up just so cannabis cultivators could measure their cannabis nutrients "feed", it fundamentally drives a difference in chemical potential of the solvent (usually water) across a semipermeable membrane(plant). EC is two things: water and salt. The concentration of both is never static, and changes as the medium goes through its wet/dry cycle, EC goes up and down, and more so as nutrients are uptaken, the soil depletes. It is a dynamic, shifting balance between water concentration and salt levels that changes constantly as your plants drink and the medium dries. What should a 4-week veg plant have for food intake? That entirely depends on the growth that the environment demands of it. EC of the medium for the 4th week of veg should be around 0.8ms/cm to 1.1ms/cm iirc, if you are looking to optimize osmotic potential and keep a clean cohesion. To translate this to your water feeding, your nutrient solution going into the medium should typically have an EC of roughly 1.2mS/cm to 1.5 mS/cm, given your run off is decent, etc. TDS ppm conversion is for the 500 scale conversion factor, as it's most commonly used for TDS over 700. Inflow(Feed) EC: 1.2mS/cm to 1.5mS/cm. (600 ppm to 750 ppm) Root Zone EC: 0.8mS/cm to 1.1mS/cm. (400 ppm to 550 ppm) Runoff EC: Slightly lower than your inflow EC. If your runoff EC is significantly higher, salts are building up; if it's lower, your plants are hungry. A plant in drought conditions can spike EC upwards of 5mS/cm, this doesn't mean the medium suddenly got 5x the "food"; only the concentration of the water solution is much lower. Important to remember that the job is to maintain the osmotic potential of the medium for the root to perform its purpose efficiently and keep bulk flow flowing. Good luck with the ladies.