coco has a 'reset button', for lack of a better term. If you get in a jam, you can mega-flush it out and make it whatever you want it to be, and it's done.
I am new, and have not really done that, but I should have, and chickened out. I will do it next grow at the first sign of a problem.
Coco needs a very heavy dose of cal-mag prior to using it to grow plants. There is science involved, but the short answer is that coco sucks the calcium until it gets full, then calcium as normal. I like coco