I use 2 vortechs on reefcrest mode, not synchronized. I have a 1500gph return pump through 2 penductors. I do not change the flow for day/night. These "eggs" were small roundish bumpy red pellets. About 1-2mm in diameter. I do run fishbowl aquatics moonlights. They run brighter and dimmer according to the lunar cycle. Have no idea what may have caused the spawn. Large piece of same coral in my frag tank (connected to main tank) did not spawn.