Karma + Ethos + Purple city PC Controlld

Go for a TDS of about 350.... Good luck!

It is impossible to discern proper color under grow lights. However, I highly doubt you would be feeding too much unless there is a ratio imbalance in your mix. 1ec is fairly low. Many plants will want more, but this depends on VPD a bit too. This will impact rate of transpiration, which will impact rate of uptake of water in the roots. Higher the vpd, the lower concentration you need to keep the plant happy. If it is drinking slower, you may find you need to up dose if you observe paling and what not... always observe and react, but knowing the cause and effect of this stuff helps choose a path better. (It's the grams of x, y,z nutes per day it needs to maintain rate of growth... the very molecules that make up the cells and their organelles. Just as same DLI over 10 hours vs 13 is virtually the same result, within reason and a photoperiod bloom context.) Hate to contradict someone, but rate of water uptake is more correlated with rate of transpiration. I'd wager when they observed these patterns for their conclusion either RH was high, temps were lower or some combination of those too. -- https://www.researchgate.net/publication/40145027_Effects_of_EC_and_fertigation_strategy_on_water_and_nutrient_uptake_of_tomato_plants This shows the water uptake in the tables by EC. Water uptake actually increased as EC rose from 1 to 2. (ignore the simulated plotted lines, RL measurements only being used here) Leaf area metric had a significant impact on water uptake, which is directly related to rate of transpiration. The conlcusion summarizes some of this and other bits are in the water uptake section. These were tomatoes, but plants are far more similar than ppl want to feel about their favorite hobby :P some exceptions exist, of course. The blotches... is it possible you dripped something on them? Or... is that a light in the canopy? The problem seems to be only in the vicinity of that light. Could be light burns being so close or even heat. Otherwise, leaves look incredibly healthy. Fat fingers. Good color underneath. Veins are proper color, etc. I would never go below 6-ish pH. What ppl say is often more cultural than real. You go below 6 and you have a higher risk of calcium and magnesium issues, which is way more important nutrients than Fe and Manganese, which is the biggest risk you face approaching 6.5 and higher. FWIW, my mix is pH buffed to around 6pH, too, but i believe it is slightly over. Just have the .5reso pH strips. I'm not suggesting 6.5, i'm just saying going lower than 6 is leaving very little room for error on important nutes, and a bit over 6 is perfectly safe with a lot more room for error. The different medium does not change the biology/chemisty occurring in the plant. It's still water with nutes dissolved in it whether standing water with clay balls or absorbed into some physical substrate. Merely a different storage setup for water. Some consistency is key with pH. It looks like you found a well-balanced mix beside those spots. You change pH and you might have to tweak the balance of mix. if you lower it, you may need a bit more Ca than before to mitigate however a lower pH impedes use of Ca... it's not the "uptake" ... roots can't distinguish between dissolved calcium and everything else dissolved in water. Some things may not physically fit, but with hydro nutes that is not a concern. Dont tweak yoour pH unless necessary. It is a hornet's nest of potential domino effects.

That is such a minor pH fluctuation I wouldn't worry about it. It is good to have some pH drift. You are using chelated nutrients, so a pH between 5.5-6.2 is completely fine. There is a study or two showing that 5.5 is optimal pH for yield etc, but that is another conversation. You are probably right about the cal-mag causing the pH drop. Calcium is a cation, so if it eats more cations than anions, the pH drops. Weeks 2-5 of flower they want the most food, so I would increase the EC and see how they handle it in your environment. Early flower they want calcium, P and always some K. Know that K is also a cation, so too much K will crash your pH as well. Those pH charts are ok, but I found it is much more complex then simply raising or lowering your EC.

while some molecules are too large to fit in through roots, the plant itself does not select what it uptkes... if it is in solution, it's coming in. You have hydro nutes, so these are all chelated/fixated/ready to be used by plant. It's all getting absorbed in this context. So, evaporation can cause a rise in EC. If soilless, as long as you get a healthy runoff (at least 10%) you should avoid any climbing EC levels. In hydro, you simply can add a proportional amount of ph'd water to fix your EC level. Your meter's error% could cause fluctuation in data collected that is not tied to any change in the water or substrate. is it also supposed to be measured at 25C? i cannot recall if that impacts measurement of EC or not... the equipment's error should be considered, if necessary. for the pH .. it's a bit concerning.. it should not shift unless microbes are causing it... evaporation will cause it to rise, but this should not be a significant amount lost to evaporation if done righ. pH is the balance of h30+ and oh- in solution... that determins acid v base, then strength is about molarity, or how much per volume... evaporation will increase whichever way it is leaning on pH scale, but like i said above, you should be limiting how much evaporation is occuring and therefore it should not be a major factor in pH swings. Microbes are the thing to worry about. they'll eat your nutes and evacuate different molecules that may be result in a different pH than before.... and they continue to do so, so it adds up quickly over time. if you aren't going below 5.8 i wouldn't worry. Good hydro nutes should be buffered. If you find swings common, try a different brand (assumes you can rule out microbial causes) Regardless of what the peanut gallery says, i would never let pH drop below 5.8. I'd stick to 6-6.2 as it is better for calcium and another molecule or two to avoid 5.8 and below. EC is easier to keep consistent.. you control the mix. If your rez is covered, should avoid effects of evaporation. A little increase due to evaporation is nothign to worry about.. if it is not minimized, you may want to find ways to reduce the rate of evaporation (like a covered rez). You should always worry about pH .. and EC. Small changes are no problem. Observe and react to plant to find those thresholds and act premeptively in future. Environment and genetics will cuase fluctuation of what a plant can and cannot handle. there is no 1 answer. If you are being careful, i'd keep eye on it but if it keeps oscillating in same small range, i'd chalk it up to equipment precision.

Honestly your plant is bulking and wants the pk right now badly. Buds will likely suffer, and lose a lot of foliage by keeping nutrition present till it is done bulking anyway.

The trichs all look pretty clear to me... some at the top are starting to turn milky but they're nowhere near what you are aiming for. I'd say you have at least 2-3 weeks left for the top buds, longer for the ones on the bottom - and there's nothing that says the entire plant has to be harvested at the same time... you can harvest the top and keep the bottom going a few weeks longer until they ripen... no harm, no foul! Good luck! The grow looks great!