Is Comprehensive the only fert you are dosing?
If so- that's most likely your problem. Comprehensive is NOT, in fact, "comprehensive" - it's mostly just micro and trace nutrients.
In a moderate to high light setting like your tank, you also need to be dosing macros (nitrogen N, phosphorus P, and potassium K).
If you want to stick with Seachem's line, they have an "enhancer pack" that is the three macros.
Or you can pick up dry ferts for much cheaper (over the long run).
If so- that's most likely your problem. Comprehensive is NOT, in fact, "comprehensive" - it's mostly just micro and trace nutrients.
In a moderate to high light setting like your tank, you also need to be dosing macros (nitrogen N, phosphorus P, and potassium K).
If you want to stick with Seachem's line, they have an "enhancer pack" that is the three macros.
Or you can pick up dry ferts for much cheaper (over the long run).