Dionae wrote:Its supposedly prewashed with a low TDS but I dont really know.
All of the brands say they are "prewashed," "naturally low in sodium," "safe for garden use," etc., and for normal use as a supplement to most regions' natural soil for plants that are more tolerant of minerals and other solubles in the soil, it's fine to use in limited quantities the same way many people normally use sphagnum peat moss to condition the soil.
BUT, the manufacturer's claims are mostly marketing hype and are only true in a relative sense, when the product is mixed with soil. Do one soak for 12-24 hours and then measure the TDS of the water you drain from the coir, and regardless of brand, the TDS is likely to be anywhere from 800 to over 1600 parts per million! (Certain death to Venus Flytraps and other carnivorous plants.)
So when used as a major ingredient in a potting mix, coir must, absolutely, positively, without question (in my opinion) be repeatedly soaked and drained perhaps 8-10 times at least, to reduce the soluble mineral salts to a usable level (between 50-70 ppm, similar to sphagnum peat moss).
So don't be fooled by the manufacturer's claims. Test it yourself and find out the truth.