doesnt really matter per say but different substrates can have varying effects on pH levels.
Also some corals can be place on the tank floor (gsp for example) so in this respect it can matter. I dont know if they prefer a small particle sand substrate as opposed to crush coral for gripping/movement but I have never seen where it really matter as far as type of coral being dependent on substrate
Also some corals can be place on the tank floor (gsp for example) so in this respect it can matter. I dont know if they prefer a small particle sand substrate as opposed to crush coral for gripping/movement but I have never seen where it really matter as far as type of coral being dependent on substrate