I've been using GH CocoTek PX in my Hempy buckets for my last three grows. Second time I used it I forgot to flush or rinse it out before planting. I lost about ten days of growth as the plants tuouffed it out and my watering/feeding finally cleaned out the salts.
So I decided to check this time around and see just how simple flushing affected the EC and PPM. I put new coco in a clean 18 oz. cup with drainage holes and ran 10 oz. of distilled water thru it. First time the run off PPM was 440. Second run thru it measured 200 and third time thru 64. Shows how fast the salts can be flushed. I use this brand because it has worked well for me and is readily available at my local hydro shop. I'm told canna is much cleaner but unfortunately not available locally for me.
Just thought I'd share.
I wish Canna was available in my area. I think it would be cleaner although I've had great results with the GH. 100% agree on bags over bricks. Unless your dealing with having it shipped, I much prefer loose bagged coco.