My betta recently had fin rot, I came home from vacation and there was a big piece of his fin missing. There's no sharp objects in the tank and it looked like fin rot, so I did a water change and added some aquarium salt and stress coat for one week in hopes to heal it. I then changed the water to get rid of the salt. It's now been a little over a month and his fin looks a little better than before, but it seems like it's stopped healing. It's not getting worse, but the growth isn't coming in fully (see pic).
My water conditions are, for the most part, always perfect, 0 ammonia, 0 Nitrite, and around 5-10 at the most Nitrate. The only problem I have is a high PH because of where I live. It's in the upper 7's, usually around like 7.8. But he's lived in this PH the whole time I've had him (like 6 months) and he's never shown any signs of stress or problems from it. But could the PH prevent his fin from growing back out fully? How long does it usually take to fully grow back out?
I did another water change last night and added some more stress coat to hopefully help the process. I understand it'll probably take awhile to grow back, just wanted to see if there's anything else I should be doing. Thanks in advance!
*You can see what his fin looked like before in my profile pic for comparison.

My water conditions are, for the most part, always perfect, 0 ammonia, 0 Nitrite, and around 5-10 at the most Nitrate. The only problem I have is a high PH because of where I live. It's in the upper 7's, usually around like 7.8. But he's lived in this PH the whole time I've had him (like 6 months) and he's never shown any signs of stress or problems from it. But could the PH prevent his fin from growing back out fully? How long does it usually take to fully grow back out?
I did another water change last night and added some more stress coat to hopefully help the process. I understand it'll probably take awhile to grow back, just wanted to see if there's anything else I should be doing. Thanks in advance!
*You can see what his fin looked like before in my profile pic for comparison.
