The link in my sig is a long-ish thread about bottom-feeding in coco, if that's of any interest to you.
... I think watering from above, like what usually happens in nature, makes sense...
Yes, you increase that chance if one or both of these situations exist: hard water, chemical salt-based nutrients.Flood & Drain, Ebb & Flow, is watering from the bottom.
With bottom watering you're increasing the chances of salt build up in the top layer of growing media.
edit; I grow in coco, shallow flood & drain, and this upper layer salt accumulation was limiting root growth in the top several inches. I now make a point of periodically hitting the top with a watering wand to wash salts back downwards. Roots now make full use of the media.
Let me take you to where the action is...Oh baby come on.