[Myka]

Crushed coral is a bit harder to swap out than sand, but it's doable. By chance, is it fine enough that you can siphon it out? If so, you are lucky, and you can simply just siphon out a 1/8th section of the cc. If not, then what you need to do is turn off all the pumps and use a gravel vacuum and clean a 1/8th section of the cc really well. Then use some sort of scoop (I would use a noodle scoop with holes in it so the water will drain) to scoop out the section that you cleaned really well. Then use a scoop (with no holes) to gently lower the sand to the bottom, and gently pour each scoop into the area where you took the cc out. Move really slowly when you are scooping out and scooping in to disturb as little as possible, but your tank will definately be cloudy. Your tank may remain cloudy for the entire time it takes to swap over, and maybe even a week after that. Turn the skimmer back on as soon as you are done, but wait a couple hours before you turn the powerheads back on. Do 1/8th of the cc twice per week so that it will take 4 weeks to complete. If you do it too fast your tank will spike ammonia and crash.