If you want premium coco coir then you want Coco Charge. Transform any coco coir into a premium growing medium. This is perfect for brick coco.
Why should you wash your coco? Because, it comes loaded with salt (Na), which is toxic to plants. It also comes loaded with way too much potassium, which will lock out other nutrients.
However, simply washing your coco medium is not enough. You see, the coco coir medium locks up salt and potassium. Washing it with water will not force the coco to let go of all the salt and potassium.
There is why you need to buffer your coco. You can buffer with Calmag but it will take using more of that product. Here is what buffering does. Calcium and Magnesium have a stronger cation exchange than salt and potassium. The calcium and magnesium forces coco to release potassium and salt and the calcium and magnesium replace them.
Oh, man, more nerdy stuff incoming. What happens if you don't buffer your coco? It screws your grow. When you feed your plant, the unbuffered coco medium releases the potassium and salt and grabs onto the calcium and magnesium you fed it. This leads to deficiencies and toxicity of potassium levels.
You don't want that and your plants don't want that, so get some Coco Charge.
Instructions: Use 8mL per gallon.
Add 8mL per gallon of Coco Charge to water. You can use tap water. Expand your coco in this charged water. Then drain and put the coco into pots and water with enough plain water until you get about a gallon of run-off for each pot. Without expanding with Coco Charge, you will need to wash with more water.
The extras EDTA in Coco Charge strips out the metals in the coco and well as help break up the salts, making it easier to wash.
Finally, make a batch of feeding water, using RO water. Add 8mL per gallon of Coco Charge, then water each pot with this and let them sit for an hour before planting any plants in them. This buffers the coco.