I'm new to the world of sumps & chaeto. I put a fist sized clump in my sump & it just sank to the bottom & sat on the sand. I assume this is not the way it should be correct? I then added a K-nano powerhead to the return section. It got it floating but not tumbling (it snags on the filter sock & it prevents it from tumbling) however I am getting good flow since the return section is only about 5 working gals (it's on a BC29 & is under the stock stand) I have one of those clip on lights with a metal reflector & a 5600K bulb that I run on opposite times of my display lights. Does it need to be tumbling or is strong flow ok?