No, by full strength I mean YOUR max ppm, not what it says on the bottle. Each strain can be different.
Go by ec or ppm, not what it says on the bottle.
As far as prepping coco-I recommend getting quality coco to start, but no matter what you get you should flush it really good before you use it.
You should be rinsing your perlite too, so to kill two birds with one stone I would make your mix of coco perlite, lets say 75/25% perlite/coco and rinse the hell out of it. Either put the mix in a big rubbermaid bin with holes drilled all through it, or a 5 gal bucket with holes if you don't need that much medium, or even empty pots. The point here is you can't run ENOUGH water through the coco. I take mine in the shower or out in my driveway and just run water through it. Warm water is good if possible-not hot but warm.
You can do this with tap water, were just trying to get rid of any excess salts and debris.
Once you have your mix nice and washed the final step is to put it into your containers and prep it by running water @ ph 5.8 through your medium with approx. 100-200ppm cal/mag. Enough for a decesnt amount of run-off. Collect a tiny bit of that run-off and check ppm, it should be same as what you put in.
Really, you just need to rinse the coco really well. The last part with the ph'd water and cal/mag is more important if your running anymore then 25%coco in your mix, I found if using RO, distilled, or really clean tap water seedlings in coco will start showing nasty cal/mag issues if I don't charge the medium with at least 100ppm cal/mag prior to planting anything in it.
Using only 25% coco in perlite/coco hempy you shouldn't run into any of the coco specific problems. If your water is really clean, or doesn't contain cal/mag then supplementing is usually needed in any medium. You'll know if you need to start supplementing with it as cal and mag issues are fairly easy to recognize.
