Coco has 20% natural aeration and holds 9x its weight in water. It also has naturally occuring growth hormones and other bio stimulants. Significant levels of soluble Calcium, Magnesium and Potassium are also found in coco. Because of its sponge like quality, and all these other qualities combined it is hard to over water and if you are paying attention, also hard to under water. These qualities also create the best sporatic root lay out of any medium on the market causing super plant growth and the largest yields you could possibly get.
I thought that coco was a bit short-on in the calcium and magnesium areas. I've read heaps here about the need to use Cal-mag or dolomite to balance this problem when using coconut coir as a medium.
Just try it! Add a little cal/mag if you need to, but try General Hydroponics Micro and Bloom at 6ml Micro, 9ml Bloom, (per gallon), every day till 5-10% runoff. If you do that, you flush out depleted nutrient solution, replenish it, and pull air down into the roots. (sorta high) Haa!