Coco/perlite run off

Just as written in your other question. If you have the feeling something is out of whack having a lockout irrigate her till input EC/PH equals runoff EC/PH with your base nutes + calmag. But 2.1 EC is not to high. Having higher output ec than input is normal. Would recommend you measuring runoff PH to check if everything is alright. Irrigate always with enough runoff, Work with the drybacks and irrigation frequency (water much more frequent than soil) and you will have lots of fun with this growing media. You can even have good results in coco when its treated like soil but you get best results if you treat it more like hydro drain to waste styl system (automated irrigation at highest level with watercontent sensor) combined with crop steering (drybacks during vegetative and generative phases)

Just give her half dose nutes next watering but water a bit more to flush our any build up of salts.

also, don't have ocd about hte numbers or what you think it should be. every adjustment should be about how the plant is behaving and growing. not some top-down unsubstantiated beliefs about what your runoff numbers should be relative to what you added.

Are you including the tap water Ec in your feeding measurement? Runoff is far from accurate as to what is in the substrate, too. religiously get at least 10% runoff and an equilibrium will result that remains consistent and relative to your formula. It may or may not be exactly what you put in but that isn't important. From there you simply adjust the formula based on what you see and the substrate will reach that new equilibrium very quickly with 10% runoff. this looks like S or Fe by the way it is paling from the inside-out on the leaves (from petiole and out). Fe would be rare. Any hydro/soilless fertilizer worth its salt would have plenty of trace elements included. So, probably a bit low on S in your formual. Try to increase S while minimizing impact on other levels of nutes as best you can. The other possibiity is slightly too intense light? that should be easy to rule out. You should try to avoid "flushing." It's a tool to use when you have a very clear and severe toxicity in the substrate. Flushing otherwise is stressful and slows down the plant for no reason. So, be more reserved when pulling that option out from the utility belt. never just give 1 type of nutrient. you are in coco. Treat it as any other soilless medium. you should be fertigating with a well-balanced and complete diet every irrigation - with 10% runoff. 1.3-1.5EC plus whatever you tap water is usually enough. Local variables does impact the concentration you need compared to another grower. This issue is minor and you can simply fix with an adjustment to your formula. Leaf symptoms are indiscrete. They do not 1:1 line up with 1 cause. So, there is always some cross-referencing needed to diagnose problems. Remember it's always easier to add things than to try to reduce concentration of something, so be patient and make sure what you see adds up to the solution you chose.

EC and PPM are one if the same. Don't need both figures. EC is more universal so better to use it. Eg. 1EC=1EC globally. However 1EC could = 500ppm or 650ppm or 700ppm depending on where you are globally. Its just measuring its conductivity in the liquid and is not 100% representative of the total dissolved solids "TDS" as sugar dissolves in water but does not affect the EC/PPM of any meter as it is not conductive. A 1.6EC = 800PPM means you are useing the 500 Scale. its common in north america. If you runoff is to high, it could be a few things. 1) you are feeding to much and need to cut it back a bit 2) you are measuring the runoff incorrectly and getting a false elevated number 3) you need more runoff 3.5) your pens need calibration. Measure your runoff after the first bit of piss comes out of the pot. The first bit is always higher, and if you let it sit in the tray it will also have dried salts that will artificially elevate the numbers. Water slowly and not too fast, Also can use a wetting agent like Yucca to help it flush out and avoid dry spots. but it works best watering a bit then waiting and watering some more. Give it time to work. but that's only if you suspect you have dry spots fucking you up.