Leaf tips on all my grows turn upwards slightly. I...

Hey there, this does not look like calmag deficiency, those curls usually indicate something to do with root problems, which seems likely after almost three months of heavy feeding , your PH is a bit high due to the Alg-a-mic which is causing some issues at the roots. Instead of a plain water feed / flush the next two weeks, try adding an enzyme to this stage, like cut out the nutes like you were going to but flush with either enzymes for two three weeks or another flushing agent the last week and hopefully it will break down the problem roots and the plant will recover just in time. Hope this helps ! 🚀