High ppm in drainage

was there a progressing problem or are you reacting to soemthing that may or may not have any effect? runoff measurement is never accurate as to what is in the substrate - it'll be impacted by anything that has dried out where the runoff goes. if no coinciding issues were occuring, this may just be normal runoff for your context. people around here sure are gangbusters about flushing for no reason, so it wouldn't be odd behaviour. it amounts to OCD behaviour as opposed to value-added. why flushing with calmag? if you have an imbalance so catastrophically bad you need to flush, it should be plain ph-balanced water. the idea is to reduce EC and then provide proper concentration and ratio of nutes or adjusted formula on a systematic path to that end. flushing without good reason only slows down your plant's growth/ripening. you are stripping building blocks away. wow you use a lot of products... lol. have you measured EC of what you feed? it's gotta be sky-high. that's most likely the problem. manic botanix has a nutrient ppm calculator you can use to tabulate the 30 things you use. if it's drastically different than 1.3-1.5 EC, then you are giving too much. a soilless substrate, as you use, should be fertilized every single irrigation. Each irrigation should religiously have 10% runoff. This eliminates buildup in substrate. It will not eliminate overfeeding and a build up occuringn in the plant. If you see symptoms, you know to adjust formula, give a little extra runoff and the new formula is in effect almost immediately. you should only flush if you think the plant is nosediving toward death, lol. not an exagerration. in soilless, you can so easily change the equilibrium in the substrate and almost immediately so. there is no reason to flush in this context unless your formula is batshit crazy off. we all need trial and error to get there. the slower the progression of any problem, the smaller the adjustment needs to be, but if you are flushing constantly that's just a lot of extra stress for no reason. about the fifty products you use -- read the ingredients. you'll find there is nothing special about any of these products and most of them could be packaged together if not for gortesque business practices of AN and their catroon labels that remind me of sugary cereal marketing ploys, lol. The only nutrient that is difficult is Ca++ becaue it canform a precipitate at high concenntrations with a couple other likely suspects involved in fertilizer. this is why you usually add the Ca containing product last to an already fully dissolved initial ingredients. if you don't, it is a good practice to start. you mostly only have to worry about a precipitate if making some concentrated stock solution with dry nutes. the liquid stuff is already diluted, but better safe than sorry. end up with a bunch of insoluble gypsum at bottom... So, my guess is that you weren't religious with 10% runoff or simply feeding WAY too much. Keep it simple. I used 4 products and could use just 3, probably. It provides 100% of what the plant needs and no illusions of grandjuer from the marketing department, lol. These nutrient ingredients are ubiquitous commodities.. there are not higher quality tiers of fertilizer ingredients.

Calibrate your ppm tester to ensure it's reading correctly. When you flush you will need to pH the water before proceeding. You'll need to run 3x the container volume through your coco. Don't bother with calmag when you flush. Just use plain water. If you have a 1 gal container you'll need to run 3 gal through it. Run that 3 gal through it fast. Douche it so there is lots of runoff. Then allow for the soil to dry out. Then resume feeding

Coco is a high irrigation system of growing. Sounds like you have not been keeping it wet or running enough through it regularly. So now you have a massive salt build up that you are trying to rinse out.