IMO, the greatest misconceived error and biggest 'Mystery Killer of Rays'.. Sure, alot of people will agree that alot of substrates will work, but only very few work well..
I had substrate so nice I would even bury myself in it to take a nap. it was very soft... (eco-complete amazon substrate... not the hard one but the sand one). so it wasnt substrate... either way, im not gonna try to figure it out... i know one thing, retics are weak and motoros are the way to go... but like i said, in the future when i have a wider tank.
last time i punched a wall i hit a stud and had to have 2 pins put in my hand to repiar it with surgery. i dont hit a wall again unless i get out a stud finger first.