My problems are ;

I cant identify positive and negative controls clearly, as negative control is giving 2.3 ish absorbance and positive control is giving 0.58. My samples are between 0.97 and 1.17

My negative control were [microalgae + medium], and my positive control were [Microalgae + DCFH + medium + treatment (H2O2)]

It is possible that im choosing my control groups are wrong, yet i havent managed to find an article that gives a detailed explanation on DCFH straining ROS method on microalgae (as it is mainly used in animal cells incubated in plate). Any help would be much appreciated.