Here's is one reason medium is important to know. This is from my super soil and coco grow, but I topped the coco with Gnat Nix.
The ceramic watering spikes worked perfectly. They are designed to work in a way where when the medium drys, the ceramic watering spike drys with the medium but the ceramic never drys fully, as it gets dry it releases more fluid, it stops releasing once the medium is wet. But.... Gnat Nix is a product that you put a layer of it over your medium and it drys fast so that if gnats lay eggs they don't survive because they dry out faster than they would in grow medium. This Gnat Nix also provides a layer between the soil so gnats can't even get to the soil to eat the roots and what not. So really everything worked how it all should have. But it was my first time using the hydro spikes and I didn't realize this wasn't going to work till my tent was flooded. What happened was when I put the spikes in the medium I pushed them in right through the Gnat Nix. The Gnat Nix did what it was suppose to and dried fast, then the ceramic watering spike did what it was supposed to and got dry fast with the flipping Gnat Nix so basically the ceramic spike was constantly drying fast and basically this created a constantly open valve. So be aware of what you do if you use the watering spiked or whatever else for that matter. Really think it out, better than me even especially when you are planning to go away and not be there. I did did this because I was trying to be a lazy fucker and just use watering spikes and amended organics soil so I wouldn't have to ever feed or water, lol or worry about any gnats. I was just like meh f'it I'm just got to fill these jugs and raise the lights once a week and see what happens, but no, this did not work out so well.
