Coco/perlite run off

I would flush with plain water and then wait 3-5 days for the soil to dry out a bit. After the drying period I would feed as normal 💯

Set up a fresh well balanced nutrient solution with the right ec and Ph and flush it with this instead of calmag only till input equals runoff and your good. Measuring runoff ph is btw also a good idea. Make sure to have always enough run off when feeding, always feed with your full solution with cal mag (base nutrients and calmag is usually enough) coco/perlite should be treated like all soilless growing media, you need to work with your drybacks in veg irrigate frequently in generative stage give longer drybacks with higher EC on the roots. Imagine when you feed your plants take up water + evaporation leaving salts in your rootzone and btw plants also release ions themselves while absorbing nutrients what you can see in circulating Hydrosystems. An EC of 2.1 is not super high for plants older than 4 weeks if everything else is fine, but if its to high for your setup reduce your dryback to keep input EC/PH closer to runoff EC/PH. Every time when you have the feeling something is out of whack having lockouts and stuff you can do this longer irrigation till Input=runoff to renew what’s inside your pot. But be aware that these are events were you overwater but since you went semi hydro with coco/perlite its not that harmfull. I use to pump air in my nutrient solution and at times also used hydrogen peroxide to have more oxygen supplied to the roots on these occasions.

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.

not a big deal just low down your feed by 25% for 1 or 2 feed and you should get back on track