Straight COCO. Use COCO specific nutrients or hydro nutrients. PH it like Hydro. 5.3-5.9. I shoot for 5.8. You water with about 20-30% run off. and check the PH of the run off to make sure it is not outside of the wanted PH range. it is about impossible to over water in coco. I use 2 gallon grow bags. COCO can be reused up 3-5 times. Even if you get nasty nat eggs in the coco, you can flush it with a double dose of hygrozym type product for 3-5 days, then give it a good flush with boiling hot water. this will kill the eggs. Of course this is after you harvest and not while the plants are growing.
It will also kill any benifitial micro organisms, but heck, coco does not have any in it when you buy it new anyway.
I never use the compressed brick type coco. that crap is to much of a pain in the butt to break up.