I’m very much running out of room for all the filtration i wanna put on my tank. My sump is a 20g long diy build with the fiji cube baffle kit. So I’m thinking instead of using the refugium section in that sump as a refugium, I’ll just hook up all my external reactors and their pumps to that section. I just have cycled rock in there at the moment, no chaeto. I have an empty 20g long from when my ball python was a baby, he’s now two years old and in a 4’x2’x2’. I want to make that into a refugium that also serves as a really pretty night light (i plan on running my lights on a reverse 12 hour cycle). I would love to make it a whole macroalgae tank that’s fully scaped out. Even though it would still be underneath the stand, i could just take one of the doors off. I have a 65g display tank but it’s on a 72"x18" stand. My AIO nano reef is on the other side of the stand. So my question is, if I wanna scape this second sump with sand instead of just rock and limited species of macroalgae, would i need to cycle it completely before connecting it to my existing system? Or can i just add fresh sand and the rock from my current sump and connect it right away? I would put a baffle between where the aquascape and the pumps are of course. I have about 100lbs of rock in my display tank already, but would adding additional water throw off the balance and potentially cause an ammonia spike? I have some relatively sensitive fish in the tank so i dont wanna do it if it could hurt them.