I had a very similar thing happen in my RCS cull tank a few weeks ago. Added 1 large Mullberry leaf, to a small tank, and a few days later it murked up. Being the cull tank i have been a bit slack on maintenance with it and the added load, coupled with a dirty filter, dirty sub, was the cause.
I removed 80% of the leaf, cleaned out the filter and did some gravel vacing, so probably changed out 50% of the water, and things were clear in a few hours. RCS can handle a big WC without problems but your CRS might not like that so much so perhaps you might just want to give one of the filters a good clean up and increase the WC to daily for a few days.
Oh and the cull tank has no light just the ambient room light so go with JayC's light reduction for sure.
Good luck.