Ph in coco

The medium is not the cause of target pH ... the type of nutes you use is the cause, which relates to soilless/hydro vs soil nutes, just for reference and to avoid bro-science. 6.5-6.8 for soil and somewhere around 6 for soilless/hydro. Don't go too low or you lock out Ca very quickly. So if you are using "soil" nutes in coco, despite it being a typical soilless medium, you need to treat it like soil in regard to nutes - probably want to amend it before use too. If you are going the soilless/hydro route with 100% plant ready and available fertilizer, then you want to be around 6 pH. Proper fertilizers for soilless growing will ph-buffer and ph-balance your water - not all of them but the ones made by real professionals will. Probably won't see that for the soil-based fertilizers.

Depends how your feeding them. anything between 5.8-7 should be fine. I am for 6.2-6.5 gives me more wiggle room should the PH drift up or down.