I do not have chaeto. wish I had room for it. I'm a bit unconventional. I do not have rocks or bricks in my sump. I have filter foam for my biological media in the sump. Several large thick flat pieces. They are crawling with pods. Some in the chamber before the sump, some in the sump chamber, and some in the chamber after the sump before the return chamber.Wow that's awesome, threebuoys! do you have chaeto in your sump? what do you have down there? i was hoping to just get away with seeding the extra live rock i have down there?