Just wondered if this is something that will settle off once EI settles in? This stuff was around before EI and stable CO2, and I take it off as and when, but I'm curious if this is something that may well continue to occur purely because the filter outlet (which is fixed in a Juwel tank) pushes water out directly under the lighting? It hasn't noticeably spread onto any other plants which are not close to the filter outlet which is good.