heres my thought buddy
any pods can and will make it to your sump , i breed mysid shrimp and i have them in my skimmer body, gfo reactors and my displays and overflow boxes are littered with them that leads me to believe that they easily make it through the pump if not at adult stage then when very young.
if you do drop a line from your fuge set it into the water enough that the bubbles wont splash over the side, close it with a valve to regulate it and dont set it down far enough so that when it first kicks in it stirs up your sand.
i would install a gatevalve on your main drain from display and a gatevalve on your tanks drain to fuge , let both run wide open when you start up the system. then tune the fuge drain to a slow drain by closing gatevalve , then tune your display the same way. should be quiet and no bubbles
i would only have a small amount of water going through personally to reduce noise, bubbles(as it will drain close to water surface)
from my experience pods and micro life end up everywhere in time anyways, the more pods you have is dependant on what you do to raise them and the predators you house with them(pretty much most fish)
i have an idea for your sump im working on a drawing ill send it over to you and let me know what you think. a sump more designed to what your doing will make everything a bit easier in terms of plumbing,drains and pump locations
