I am hoping to get a Mandarin and a Melanurus wrasse for my 65g so I need a large pod population if the Mandarin won't eat frozen. This tank was upgraded from a 32g cube in November and I have a ton of pods, but I'm sure I will need more. I'm trying to figure out where I can put a refugium. My sump seems pretty small and I can't do a HOB on the display as I have a custom lid. Can I add a HOB refugium on my sump? Or if anyone has any other ideas, please feel free to share. Here is a photo of my sump.