I use cheap bricks, but I strain out much of the peat, rinse out all the salt, do two 8-12 hour soaks in a solution of calmag, and then it becomes top-grade coco. If you can't strain out a lot of the peat, then just use more perlite, like 50/50 ratio. I go straight coco in 1 gallon pots.
You don't want drybacks. It's supposed to stay 90%+ saturated at all times. Properly prepared coco provides enough oxygen.
To test EC just put the brick in a bucket and fill it with distilled water and break apart the brick, or just use tap water and take a reading of the tap's EC first. After the brick is separated, dip your EC meter in there and see how much higher it is than the starting water's EC.
As for rinsing, just put it in a strainer and rinse with a garden hose. It doesn't take long to get the salt out and you'll also get out the peat.
