CoachB, I would not rake or stir chara as it will spread. If your going to treat it consider Cutrine Granular as soon as the water in the 3-4 ft range averages at least 50F. Once it turns white it can be raked. Have had no luck with GreenClean on chara.Even though you will read that one application of Cutrine granular should do it be prepared for an early spring and summer treatment. Have also found that if dying the water is in the plan to use an equal part of black dye with a blue acid.Seems to work better than the standard blue/yellow dyes like Aquashade for chara control. If dying the water aeration prior a must.Be sure you are treating "chara"as it can be confused.If you are seeing some FA this winter it is probably spirogyra and will die off when it warms up but may be replaced with lyngbya or pithophora. Once you eliminate the chara be prepared for additional FA as is often the downside to chara elimination.You may then find using some Greenclean on these FA's work as you will have warmer temps.If GreenClean does not not oxidize it out other options exist to spot spray such as Cutrine Plus liquid with diquat and a surfactant. This approach would leave you the option for other rooted plants to get established.If your FA gets windblown or bunched up it will die off faster if it is broken up first as this promotes better coverage.