I'm planning a sump for the 125 gallon I'm setting up using 2 20 longs and a bulkhead to connect them. in the first one I plan on having a felt filter mat on top of some marine blocks instead of filter socks. then the protein skimmer and the heaters in the second tank I'm going to have a refugium with macro algae and a return pump planning on using course filter sponge to divide sections mainly the refugium from the return pump. Wondering if I can/should use the sand from my current tank in the refugium its full of bristle worms? any thought?