I used the coco for 2 years now, i can tell you it's the BEST stuff in the world..all my friends turn for coco after the see my results...This story of potassium is crap, wtf, where he hear that???
Also, the PH is 100% STABLE, it's come around 6 or 6.5 but after 2 or 3 times watering the coco it's will reach 5.8 and if you always calibrate you water to 5.8 the stuff will stick to it and be 100% stable.
Anyway, the most important thing is to buy a GOOD brand, the best is Canna Coco in bag of 50 liters, the main reason is the PH and SALT, because coco come from the south an is grow closed to the sea, it's could contains SALT and salt is a nutriment lock for the plant. So use Canna Coco and you are 100% safe, they clean the coco and caliber the PH, also the add tricoderm for protect the product and plants from bacteria.
the price of a bag is more high than dirt but i reused the stuff for 1 year (6 crops), you don't have to mix anything, don't add perlite or other stuff, Coco is made for use like it is.
Even beter after the second crop you get better result than the first because the coco stuff is 100% stable.
I water by hand once every 4 to 5 days in small 3 liters (6'') container. Before ,In dirt, i was using 8'' container but the coco is holding 10 times is weight of water, with smaler container i can fit more plants under 1 lamp and have the yeild per plant.
Even if i used smaler containers i get more roots than before, coco is more soft so roots develop faster.
Also the good part, better than dirt, is about the air in the coco, it's impossible to over-water the coco, in fact when you give water you have OVER WATER the plants each time and have at least 1 cup of water dripping from the bottom of the container event if you have more water dripping it's better, me i let about 1 liter of water driping, this rince the over nutriment each time you water, so no need to make any watering with low ppm during the crop, but it's also important to let the plants dry the coco the most possible befor each watering. This thing is amazing even after transplanting your clones and over-watering the coco, the leaf stay high.
Other thing to know is the PH, When growing in coco you have to use 5.8 (not 6.3 like dirt) Coco is hydroponic stuff also at the harvest the THC level is more high like in pure hydroponic when i do my hash i have the double than before.
For best result, used the Canna Coco nutriment A+B, they are designed for that stuff, regular nutriment solution is not well taked by the plants in the coco and this is where PH come unstable, troubles come this nutriment absorbtion and where you lost your plants, so this is the main reason why is better to used Canna Coco A+B they are more expensive but you are sure to have the best result also you take less stuff each time you make your mixture, you have to lower a bit the concentration.
also those nutriment are 100% completed with folic acid, even if it's a bit more expensive you get more weight at the end and have no side product to add (only bloom booster).
Using this stuff give you the best result. For the part of bloom booster you can use regular liquid PK 13/14 that work well and it's cheap.
Last crop i have try to used a product call Atami Bloombastic it's a pk 20/21 with lots of mineral, more complete product on the market and i raise my result of 20% just by using this stuff with A+B, nothing else, this stuff is $$$$$, but so concentrate it's good for lots of crops (used only 0.5ml/liters) and it's pay by itself with the result.
One thing t know when you make your mixture, do it 24h before watering, doing this ensure you that the PH will be 100% stable before watering, i use the same coco soil for one year and if i take the water that drips from the container and check the PH it's will be at 5.8 stable.
When reused the coco, empty your container, remove the big roots, refill the container and plant your clones...After for your first 3 water time add enzyme solution (like Cannazym) for help destroy the rest of small roots.
Like you see i always use most of the time Canna brand, i'm sure the product will be perfectly cmpatible with the stuff.
Other good part for this medium is, NO BUGS, the dirt come from outside and sometimes with eggs, coco come from tree.
Also if you have problem with high humidity level, coco will help you ther, because the coco do not release humidity, i have lower my room of 20% with that stuff.
Other thing, the dirt become compact after some watering, with coco you never have this problem, the soil stay always soft and when you add water, event if it's at 99% dry, the coco take the water like a sponge.
When you change the coco just throw it on the garden like dirt.