Agreed that your alk is too high at 11but raised over two weeks would not be a problem. Phosphate at .04 is not lowAlk swings is stressful. Running high alk with low nutrient is also like playing with fire. You will have people tell you all these amazing tanks that run high alk but there's a reason most reputable LFS runs alk between 6-8. Going from 9-11 over two weeks may have been the breaking point along with the low 0.04 phosphate.