you need to reach the bottom of your tank, i would go with nothing deeper than i could reach. just a thought. small access holes dont leave much room for large rock or mobility inside the tank...
look for your "parasite" at reefcentral cause thats what i think-know it is. i had them, they are cyo---- i dont remember, i just know how i got rid of mine was a 6line wrasse, he loved them...lol they burrow under the scales and eat your fish from inside until they die then move to another...
i like the idea, thought a little input on the copper fixture might help. p.v.c. although its more flexable, unless you choose larger O.D. would be a choice. close to the bottom use a tee and L (*90)to go behind the stand and possibly in front as well, for stability. kinda like a "small" letter...