Well, if all your feeding is Alaskan fish fert, then it's definitely not burnt. It looks like a calmag deffenicy to me. Had one with my past crop that looked very similar to yours. Also, your ph on your water is way to high bro. Shoot for around 6.5 no higher, no lower than 6.0. I bet if you give her a nice dose of calmag you'll start to see her perk up. The leaves that are brown/burnt looking for the most part will not recover. What I do is take a pair of snips and clip off those parts.
Np. Well, the reason why I said I don't think it's nute burn is bc the Alaskan ferts your using really doesn't have enough N in it to do much burning. I use to use that on top of my regular nutes a few yrs back. Yeah, it wouldn't hurt to add the Epsom salt at all. I'd start with a foiler feeding with the es, followed by adding some to your gallon of h20. It also makes sense for it to be calmag being that your ph is on the high side, it tends to lock out nutrients such as calcium and magnesium with higher ph. So once you get that straight you should be golden.
Np. If you ever need any further help down the road, feel free to shoot me a pm, I'd be glad 2 help.
You can. Wouldn't hurt um. I just remove the dead parts is all I do. I cut them like you would cut a a clone leaf. Wouldn't hurt to leave them, it'll just clean her up is all.