you can go by directions ,or you can take the word of many growers
remember this and decide for your self
coco has nothing to feed a plant,it is like a chinese resturant,you go there and eat nothing but fillers 2 hours later your hungry again,
same thing with coco ,you feed it in a couple hours feed again and repeat,the whole idea behind coco is that you force feed the plants from cation exchange,you cant over water it,you never let it dry,you never just give it water,always something,even if it is just a low dose of cal mag,again never just water,even though running water threw it does exchange the air,it also makes the plant expelled stored nutrients ,so yes it is a waste of nutrients,but it not ,why you ask,because your force feeding the plant,the more you feed it the quicker and bigger the plant becomes.
that said you can go to big in the indoor setting in my opinoin,first off start your seed in a solo cup ,when it get 3 sets full leaves straight into a 3 gal pot,this is to keep some of the waste down,if you go to a 7 gal pot,like some recomend you really waste nutes and dont help you at all ,again my opinion,they claim if you grow in a 7 gal pot you can get away with feeding once a day,that is true,but throws the therory out the window.
your force feeding the plant,feeding once a day harms it ,twice a day makes that bitch call you daddy,they love the air and nute exchange and show you ,the 7 gal pot will grow of course but feeding once a day ,and if you dont feed to a really good runoff every time ,will, build salt buildup quicker,coco is grown around salt water right,anyway maybe this crap i wrote help you understand that growing in coco is labor and nute waste but it will shol enough fill jars quicker than soil,and when your old ass back cant handle much anymore ,that work for a coco grow might hurt your ass but you be setting back smoking the end game a lot quicker and longer if you do it right,i grow once a year,i start a soil grow ,take cuts and coco grow the cuts,the coco grow beats out the soil grow by a month ,so in the 5 months i grow i fill jars that last me 2 years minumum of smokable product