Well even though I only lost .5 overnight it is algae.

My wife took a sample to school and looked at it under the microscope. Last week I did notice my FC was 2.5 so maybe it came back sometime then. I still have been adjusting the SWCG to get it where it was and must have had the purifier to low.

So it looks like a shock is in my future in the next couple days, whenever I get a chance.