Well if your skimming 24/7 and replacing the carbon every week it should be getting rid of most if not all of the toxins.
Other then the pale area near the bottom on the yuma, I don't see anything wrong with it. How old are your lights? It could just be a lighting issue where it's getting too much or too little. You could try moving it in a shaded area and see how it reacts or try moving it up.
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